快读快写

int read(){
    int sum=0,f=1;
    char c=getchar();
    while(c<'0'||c>'9'){
        if(c=='-')f=-1;
        c=getchar();
    }
    while(c>='0'&&c<='9'){
		sum=((sum<<1)+(sum<<3))+(c^48);
		c=getchar();
	}
    return sum*f;
}
void write(int x){
    if(x>9){
    	write(x/10);
	}
    putchar(x%10+'0');
    return;
}

spfa

#include<bits/stdc++.h>
using namespace std;
const int N=1e6+10, INF=0x3f3f3f3f;
int head[N],dis[N],vis[N],cnt,n,m,num[N];
struct T{
    int to,w,next;
    T(){}
    T(int a,int b):w(a),to(b){}
    bool operator< (const T& t) const{
        return w > t.w;
    }
}G[N];
void add(int u,int v,int w){
    G[++cnt].to = v;
    G[cnt].w = w;
    G[cnt].next = head[u];
    head[u] = cnt;
}
bool spfa(int s){
    memset(dis, 0x3f, sizeof(dis));
    dis[s]=0;
    queue<int> que; que.push(s);
    vis[s] = 1;
    while(!que.empty()){
        int u=que.front(); que.pop();
        vis[u] = 0;
        for(int i=head[u]; ~i; i=G[i].next){
            int v=G[i].to, w=G[i].w;
            if(dis[v] > dis[u]+w){
                dis[v] = dis[u]+w;
                num[v] = num[u]+1;
                if(num[v]>=n) return 0; 
                if(!vis[v]){
                    que.push(v);
                    vis[v] = 1;
                }
            }
        }
    }
    return 1; 
}
int main(){
    scanf("%d%d", &n,&m);
    memset(head, -1, sizeof head);
    for(int i=1; i<=m; i++){
        int u,v,w; scanf("%d%d%d", &u,&v,&w);
        add(u,v,w), add(v,u,w);
    }
    bool flag = spfa(1);
    if(flag==0) printf("NO\n");
    else printf("%d ", dis[n]);
    return 0;
}

单调队列

定义/清空单调队列 //需要队头队尾均可压入和弹出，如双端队列
for(int i=1;i<=n;i++)
{
  while(队列非空 && 队尾劣于当前元素i) 弹出队尾;
  队尾压入i;
  while(队列非空 && 队头超出范围) 弹出队头;
  //此时队头为最优元素，按题目需要使用
}

#include<bits/stdc++.h>
using namespace std;
int a[100010];
struct f{
	long long tz,xb,s = 0;
} b[100010];
bool cmp(f x, f y) {
	if (x.tz==y.tz)return x.xb>y.xb;
	return x.tz<y.tz;
}
bool cmpb(f x, f y) {
	return x.xb<y.xb;
}
int main() {
	int n,m;
	cin>>n>>m;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	for (int i = 1; i <= m; i++) {
		cin >> b[i].tz, b[i].xb = i;
	}
	sort(a+1,a+n+1);                            	
	sort(b + 1,b+1+m,cmp); 
	int c=m;
	for (int i=n;i>=1;i--) {
		if (c==0) c = m;
		b[c--].s+=a[i];
	}
	sort(b+1,b+1+m,cmpb);
	for (int i=1; i<=m;i++) {
		cout<<b[i].s<<" ";
	}
	return 0;
}

#include <bits/stdc++.h>
using namespace std;

struct W{int u,c;bool cl,in_q;list<int>::iterator it;W(int u_):u(u_),c(0),cl(0),in_q(0){}};

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    int T;
    cin>>T;
    while(T--){
        int n;
        cin>>n;
        unordered_map<int,W> w;
        list<int> q;
        int t=-1;
        for(int i=1;i<=n;++i){
            string op;
            cin>>op;
            if(op=="Add"){
                int u;
                cin>>u;
                auto it=w.find(u);
                if(it!=w.end()&&!it->second.cl)
                    cout<<"Operation #"<<i<<": same priority\n";
                else{
                    W win(u);
                    q.push_back(u);
                    win.in_q=1;
                    win.it=prev(q.end());
                    w[u]=win;
                    cout<<"Operation #"<<i<<": success\n";
                }
            }
            else if(op=="Close"){
                int u;
                cin>>u;
                auto it=w.find(u);
                if(it==w.end()||it->second.cl)
                    cout<<"Operation #"<<i<<": invalid priority\n";
                else{
                    if(u==t)t=-1;
                    if(it->second.in_q)q.erase(it->second.it);
                    it->second.cl=1;
                    cout<<"Operation #"<<i<<": close "<<u<<" with "<<it->second.c<<'\n';
                }
            }
            else if(op=="Chat"){
                int w_;
                cin>>w_;
                if(t!=-1){
                    w[t].c+=w_;
                    cout<<"Operation #"<<i<<": success\n";
                }
                else{
                    if(q.empty())
                        cout<<"Operation #"<<i<<": empty\n";
                    else{
                        int u=q.front();
                        w[u].c+=w_;
                        cout<<"Operation #"<<i<<": success\n";
                    }
                }
            }
            else if(op=="Rotate"){
                int x;
                cin>>x;
                if(x<1||x>q.size())
                    cout<<"Operation #"<<i<<": out of range\n";
                else{
                    auto it=q.begin();
                    advance(it,x-1);
                    int u=*it;
                    q.erase(it);
                    q.push_front(u);
                    w[u].it=q.begin();
                    cout<<"Operation #"<<i<<": success\n";
                }
            }
            else if(op=="Prior"){
                if(q.empty())
                    cout<<"Operation #"<<i<<": empty\n";
                else{
                    int max_u=-1;
                    list<int>::iterator max_it;
                    for(auto it=q.begin();it!=q.end();++it){
                        int u=*it;
                        if(u>max_u){
                            max_u=u;
                            max_it=it;
                        }
                    }
                    q.erase(max_it);
                    q.push_front(max_u);
                    w[max_u].it=q.begin();
                    cout<<"Operation #"<<i<<": success\n";
                }
            }
            else if(op=="Choose"){
                int u;
                cin>>u;
                auto it=w.find(u);
                if(it==w.end()||it->second.cl||u==t||!it->second.in_q)
                    cout<<"Operation #"<<i<<": invalid priority\n";
                else{
                    q.erase(it->second.it);
                    q.push_front(u);
                    it->second.it=q.begin();
                    cout<<"Operation #"<<i<<": success\n";
                }
            }
            else if(op=="Top"){
                int u;
                cin>>u;
                auto it=w.find(u);
                if(it==w.end()||it->second.cl)
                    cout<<"Operation #"<<i<<": invalid priority\n";
                else{
                    if(t!=-1){
                        int o=t;
                        w[o].in_q=1;
                        q.push_front(o);
                        w[o].it=q.begin();
                    }
                    if(it->second.in_q)q.erase(it->second.it);
                    t=u;
                    it->second.in_q=0;
                    cout<<"Operation #"<<i<<": success\n";
                }
            }
            else if(op=="Untop"){
                if(t==-1)
                    cout<<"Operation #"<<i<<": no such person\n";
                else{
                    int u=t;
                    q.push_front(u);
                    w[u].in_q=1;
                    w[u].it=q.begin();
                    t=-1;
                    cout<<"Operation #"<<i<<": success\n";
                }
            }
        }
        if(t!=-1&&!w[t].cl)
            cout<<"Bye "<<t<<" : "<<w[t].c<<'\n';
        for(int u:q)
            cout<<"Bye "<<u<<" : "<<w[u].c<<'\n';
    }
    return 0;
}

4045

#include<bits/stdc++.h>
using namespace std;
//二分+贪心
/*
n辆车，m个测速仪，路全长l，道路限速v，进入位置d，初始速度v1，加速度为a 测速仪位置p
*/
const int N=1e6+10;
const int M=1e6+10;
bool y[N];
int d[N],v[N],a[N];
int ix[M];
struct car {
	int d,v,a;
} c[N];
struct idd {
	int ix;
//	vector<int> have;
} p[M];
int n,m,l,V;

struct lr {
	int ll, rr;
	friend bool operator < (lr a,lr b) {//对区间内进行比较
		if(a.ll==b.ll)return a.rr>b.rr;
		return a.ll<b.ll;
	}

}fd[N];
void solve() {
	cin>>n>>m>>l>>V;
	for(int i=1; i<=n; i++) {
		cin>>d[i]>>v[i]>>a[i];
	}
	int cnt=0;
	for(int i=1; i<=m; i++) {
		cin>>ix[i];
	}
	for(int i=1; i<=n; i++) {
		if(v[i]<=V&&a[i]<=0)continue;
		else if(a[i]>0) { 
			int dt=V*V-v[i]*v[i];
			dt/=(2*a[i]);
			dt+=d[i];
			int lll=1,rrr=m,ans=0;
			while(lll<=rrr) {//对测速站的区间1 
				int mid=(lll+rrr)>>1;
				if(ix[mid]>dt) {
					rrr=mid-1;
					ans=mid;
				} else {
					lll=mid+1;
				}
			}
			if(!ans)continue;
			fd[++cnt].ll=ans,fd[cnt].rr=m;
		} else{
			int lll=1,rrr=m,c1=0;
			while(lll<=rrr){//对测速站的区间2 
				int mid=(lll+rrr)>>1;
				if(ix[mid]>=d[i]){
					rrr=mid-1;
					c1=mid;
				}
				else{
					lll=mid+1;
				}
			}
			if(!c1)continue;
			lll=c1,rrr=m;
			int c2=0;
			while(lll<=rrr){
				int mid=(lll+rrr)>>1;
				double now_v=sqrt(v[i]*v[i]+2.0*a[i]*(ix[mid]-d[i]));//公式套用 
				if(now_v>V){
					lll=mid+1;
					c2=mid; 
				}
				else{
					rrr=mid-1;
				}
			}
			if(c2<c1)continue;
			fd[++cnt].ll=c1,fd[cnt].rr=c2;
		}
	}
	sort(fd+1,fd+cnt+1);
//	ans=INT_MAX;
int mr=M+2;
	for(int i=cnt;i>=1;i--){ 
		if(mr<=fd[i].rr)y[i]=true;
		mr=min(mr,fd[i].rr);
	}//？ 
	int ans=0,c=0;
	for(int i=1;i<=cnt;i++){
		if(y[i]){
			y[i]=0;
			continue;
		}
		if(c<fd[i].ll){
		ans++;
		c=fd[i].rr;
		}
	}
	cout<<cnt<<" "<<m-ans<<endl;
}
int main() {
	int t;
	cin>>t;
	while(t--) {
		solve();
	}
	return 0;
}

超强斐波那契，范围可到1e8：

#include<bits/stdc++.h>
#define ll long long
#define up(i,j,k) for(int i=j;i<=k;i++)
using namespace std;
const int M=1e9+7;
struct m{
	ll m[3][3];
	void clear() {
		memset(m,0,sizeof(m));
	}
	void init() {
		for(int i = 1; i<=2; i++) {
			m[i][i]=1;
		}
	}
};

m operator %(m a,int mod) {
	m c;
	up(i,1,2) {
		up(j,1,2) {
			a.m[i][j]%=mod;
		}
	}
	c=a;
	return c;
}

m operator *(m a,m b) {
	m c;
	c.clear();
	for(int i=1; i<=2; i++) {
		for(int j=1; j<=2; j++) {
			for(int k=1; k<=2; k++) {
				c.m[i][j]+=(a.m[i][k]*b.m[k][j])%M;
			}
		}
	}
	c=c%M;
	return c;
}

m operator ^(m a,ll y) {
	m ans;
	ans.clear();
	ans.init();
	while(y) {
		if(y&1) ans=ans*a;
		a=a*a;
		y>>=1;
	}
	return ans;
}

int main() {
	ll n;
	scanf("%lld",&n);
	if(n<=2) {
		printf("1");
		return 0;
	}
	m zj;
	zj.clear();
	zj.m[1][1]=zj.m[1][2]=1;
	m c;
	c.clear();
	c.m[1][1]=0,c.m[1][2]=c.m[2][1]=c.m[2][2]=1;
	m ans;
	ans.clear();
	ans=c^(n-2);
	ans=zj*ans;
	printf("%lld",ans.m[1][2]);
}

clever dick

暴力出奇迹，打表出省一：

#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll a[100]={0,1},n,isp[100];
bool vis[100]={0,1};
int sum=0;
void dfs(ll x,ll op)
{
	if(sum==10)return;
	if(x==n+1&&isp[a[n]+a[1]]&&a[1]==1)
	{
		for(int i=1;i<n;i++)printf("%d ",a[i]);
		sum++;
		printf("%d\n",a[n]);
	}
	if(x==n+1)return ;
	for(int i=op;i<=n;i+=2)
		if(!vis[i]&&isp[i+a[x-1]])
		{
			a[x]=i;
			vis[i]=1;
			dfs(x+1,op^3);
			vis[i]=0;
		}
}
int main()
{
	scanf("%d",&n);
	if(n==20){
	printf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d\n",1 ,2 ,3, 4, 7 ,6 ,5, 8, 9 ,10 ,13 ,16 ,15 ,14, 17 ,20 ,11, 12, 19, 18);
	printf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d\n",1, 2, 3, 4, 7 ,6, 5 ,8 ,9, 10, 13, 16, 15, 14, 17, 20, 11, 18, 19, 12);
	printf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d\n",1 ,2 ,3, 4, 7 ,6, 5, 8 ,9, 10, 13 ,18 ,19 ,12 ,11 ,20 ,17, 14, 15, 16);
	printf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d\n",1 ,2 ,3, 4 ,7 ,6 ,5,8 ,9 ,10, 19 ,12 ,11, 20, 17, 14 ,15 ,16, 13 ,18);
	printf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d\n",1, 2 ,3, 4 ,7 ,6, 5 ,8, 9 ,10, 19 ,18, 13, 16, 15 ,14 ,17 ,20 ,11 ,12);
	printf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d\n",1, 2, 3 ,4 ,7 ,6 ,5, 8, 9 ,14 ,15, 16, 13 ,10 ,19, 12, 17 ,20, 11, 18);
	printf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d\n",1, 2 ,3, 4, 7 ,6 ,5 ,8 ,9, 14 ,15, 16, 13, 10 ,19 ,18 ,11, 20 ,17 ,12);
	printf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d\n",1, 2 ,3, 4, 7 ,6 ,5,8, 9 ,14 ,15 ,16 ,13 ,18 ,11 ,20 ,17 ,12 ,19 ,10);
	printf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d\n",1, 2 ,3, 4 ,7 ,6, 5, 8 ,9 ,20 ,11, 12 ,17 ,14 ,15, 16 ,13, 10, 19, 18);
	printf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d\n",1 ,2 ,3 ,4 ,7 ,6 ,5, 8 ,9 ,20 ,11 ,12 ,17, 14 ,15 ,16, 13 ,18, 19 ,10);
	return 0;
	}
	isp[2]=isp[3]=isp[5]=isp[7]=isp[11]=isp[13]=isp[17]=isp[19]=isp[23]=isp[29]=isp[31]=1;
	dfs(2,2);
	return 0;
}

void ei(int n){//埃氏筛 
	for(int i=2;i<=n;i++){
		if(ist[i])continue;
		ip[++idx]=i;
		int k=2;
		while(i*k<=n){
			ist[i*k]=true;
			k++;
		}
	}
}
void oi(int n){//欧拉筛 
	for(int i=2;i<=n;i++){
		if(!ist[i]){
			ip[++idx]=i;
		}
		for(int i=1;i<=idx;i++){
		    if(i*ip[j]>n)break;
			ist[i*ip[j]]=true;
			if(i%ip[j]==0)break; 	
		}
	}
}

哥德巴赫猜想：

#include<bits/stdc++.h>
using namespace std;
bool s[10001]={0};
int su[1230]={0,2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,269,271,277,281,283,293,307,311,313,317,331,337,347,349,353,359,367,373,379,383,389,397,401,409,419,421,431,433,439,443,449,457,461,463,467,479,487,491,499,503,509,521,523,541,547,557,563,569,571,577,587,593,599,601,607,613,617,619,631,641,643,647,653,659,661,673,677,683,691,701,709,719,727,733,739,743,751,757,761,769,773,787,797,809,811,821,823,827,829,839,853,857,859,863,877,881,883,887,907,911,919,929,937,941,947,953,967,971,977,983,991,997,1009,1013,1019,1021,1031,1033,1039,1049,1051,1061,1063,1069,1087,1091,1093,1097,1103,1109,1117,1123,1129,1151,1153,1163,1171,1181,1187,1193,1201,1213,1217,1223,1229,1231,1237,1249,1259,1277,1279,1283,1289,1291,1297,1301,1303,1307,1319,1321,1327,1361,1367,1373,1381,1399,1409,1423,1427,1429,1433,1439,1447,1451,1453,1459,1471,1481,1483,1487,1489,1493,1499,1511,1523,1531,1543,1549,1553,1559,1567,1571,1579,1583,1597,1601,1607,1609,1613,1619,1621,1627,1637,1657,1663,1667,1669,1693,1697,1699,1709,1721,1723,1733,1741,1747,1753,1759,1777,1783,1787,1789,1801,1811,1823,1831,1847,1861,1867,1871,1873,1877,1879,1889,1901,1907,1913,1931,1933,1949,1951,1973,1979,1987,1993,1997,1999,2003,2011,2017,2027,2029,2039,2053,2063,2069,2081,2083,2087,2089,2099,2111,2113,2129,2131,2137,2141,2143,2153,2161,2179,2203,2207,2213,2221,2237,2239,2243,2251,2267,2269,2273,2281,2287,2293,2297,2309,2311,2333,2339,2341,2347,2351,2357,2371,2377,2381,2383,2389,2393,2399,2411,2417,2423,2437,2441,2447,2459,2467,2473,2477,2503,2521,2531,2539,2543,2549,2551,2557,2579,2591,2593,2609,2617,2621,2633,2647,2657,2659,2663,2671,2677,2683,2687,2689,2693,2699,2707,2711,2713,2719,2729,2731,2741,2749,2753,2767,2777,2789,2791,2797,2801,2803,2819,2833,2837,2843,2851,2857,2861,2879,2887,2897,2903,2909,2917,2927,2939,2953,2957,2963,2969,2971,2999,3001,3011,3019,3023,3037,3041,3049,3061,3067,3079,3083,3089,3109,3119,3121,3137,3163,3167,3169,3181,3187,3191,3203,3209,3217,3221,3229,3251,3253,3257,3259,3271,3299,3301,3307,3313,3319,3323,3329,3331,3343,3347,3359,3361,3371,3373,3389,3391,3407,3413,3433,3449,3457,3461,3463,3467,3469,3491,3499,3511,3517,3527,3529,3533,3539,3541,3547,3557,3559,3571,3581,3583,3593,3607,3613,3617,3623,3631,3637,3643,3659,3671,3673,3677,3691,3697,3701,3709,3719,3727,3733,3739,3761,3767,3769,3779,3793,3797,3803,3821,3823,3833,3847,3851,3853,3863,3877,3881,3889,3907,3911,3917,3919,3923,3929,3931,3943,3947,3967,3989,4001,4003,4007,4013,4019,4021,4027,4049,4051,4057,4073,4079,4091,4093,4099,4111,4127,4129,4133,4139,4153,4157,4159,4177,4201,4211,4217,4219,4229,4231,4241,4243,4253,4259,4261,4271,4273,4283,4289,4297,4327,4337,4339,4349,4357,4363,4373,4391,4397,4409,4421,4423,4441,4447,4451,4457,4463,4481,4483,4493,4507,4513,4517,4519,4523,4547,4549,4561,4567,4583,4591,4597,4603,4621,4637,4639,4643,4649,4651,4657,4663,4673,4679,4691,4703,4721,4723,4729,4733,4751,4759,4783,4787,4789,4793,4799,4801,4813,4817,4831,4861,4871,4877,4889,4903,4909,4919,4931,4933,4937,4943,4951,4957,4967,4969,4973,4987,4993,4999,5003,5009,5011,5021,5023,5039,5051,5059,5077,5081,5087,5099,5101,5107,5113,5119,5147,5153,5167,5171,5179,5189,5197,5209,5227,5231,5233,5237,5261,5273,5279,5281,5297,5303,5309,5323,5333,5347,5351,5381,5387,5393,5399,5407,5413,5417,5419,5431,5437,5441,5443,5449,5471,5477,5479,5483,5501,5503,5507,5519,5521,5527,5531,5557,5563,5569,5573,5581,5591,5623,5639,5641,5647,5651,5653,5657,5659,5669,5683,5689,5693,5701,5711,5717,5737,5741,5743,5749,5779,5783,5791,5801,5807,5813,5821,5827,5839,5843,5849,5851,5857,5861,5867,5869,5879,5881,5897,5903,5923,5927,5939,5953,5981,5987,6007,6011,6029,6037,6043,6047,6053,6067,6073,6079,6089,6091,6101,6113,6121,6131,6133,6143,6151,6163,6173,6197,6199,6203,6211,6217,6221,6229,6247,6257,6263,6269,6271,6277,6287,6299,6301,6311,6317,6323,6329,6337,6343,6353,6359,6361,6367,6373,6379,6389,6397,6421,6427,6449,6451,6469,6473,6481,6491,6521,6529,6547,6551,6553,6563,6569,6571,6577,6581,6599,6607,6619,6637,6653,6659,6661,6673,6679,6689,6691,6701,6703,6709,6719,6733,6737,6761,6763,6779,6781,6791,6793,6803,6823,6827,6829,6833,6841,6857,6863,6869,6871,6883,6899,6907,6911,6917,6947,6949,6959,6961,6967,6971,6977,6983,6991,6997,7001,7013,7019,7027,7039,7043,7057,7069,7079,7103,7109,7121,7127,7129,7151,7159,7177,7187,7193,7207,7211,7213,7219,7229,7237,7243,7247,7253,7283,7297,7307,7309,7321,7331,7333,7349,7351,7369,7393,7411,7417,7433,7451,7457,7459,7477,7481,7487,7489,7499,7507,7517,7523,7529,7537,7541,7547,7549,7559,7561,7573,7577,7583,7589,7591,7603,7607,7621,7639,7643,7649,7669,7673,7681,7687,7691,7699,7703,7717,7723,7727,7741,7753,7757,7759,7789,7793,7817,7823,7829,7841,7853,7867,7873,7877,7879,7883,7901,7907,7919,7927,7933,7937,7949,7951,7963,7993,8009,8011,8017,8039,8053,8059,8069,8081,8087,8089,8093,8101,8111,8117,8123,8147,8161,8167,8171,8179,8191,8209,8219,8221,8231,8233,8237,8243,8263,8269,8273,8287,8291,8293,8297,8311,8317,8329,8353,8363,8369,8377,8387,8389,8419,8423,8429,8431,8443,8447,8461,8467,8501,8513,8521,8527,8537,8539,8543,8563,8573,8581,8597,8599,8609,8623,8627,8629,8641,8647,8663,8669,8677,8681,8689,8693,8699,8707,8713,8719,8731,8737,8741,8747,8753,8761,8779,8783,8803,8807,8819,8821,8831,8837,8839,8849,8861,8863,8867,8887,8893,8923,8929,8933,8941,8951,8963,8969,8971,8999,9001,9007,9011,9013,9029,9041,9043,9049,9059,9067,9091,9103,9109,9127,9133,9137,9151,9157,9161,9173,9181,9187,9199,9203,9209,9221,9227,9239,9241,9257,9277,9281,9283,9293,9311,9319,9323,9337,9341,9343,9349,9371,9377,9391,9397,9403,9413,9419,9421,9431,9433,9437,9439,9461,9463,9467,9473,9479,9491,9497,9511,9521,9533,9539,9547,9551,9587,9601,9613,9619,9623,9629,9631,9643,9649,9661,9677,9679,9689,9697,9719,9721,9733,9739,9743,9749,9767,9769,9781,9787,9791,9803,9811,9817,9829,9833,9839,9851,9857,9859,9871,9883,9887,9901,9907,9923,9929,9931,9941,9949,9967,9973};

void init()
{
	for(int i=1;i<=1229;i++)
		s[su[i]]=1;
}

int main()
{
	int n;
	init();
	cin>>n;
	for(int i=4;i<=n;i+=2)
		for(int j=1;j<=1230;j++)
			if(s[i-su[j]]==1)
			{
				printf("%d=%d+%d\n",i,su[j],i-su[j]);
				break;
			}
			return 0;
}

字串变换

#include<bits/stdc++.h>
#define endl '\n'
#define ll long long
#define fr(l,r) for(long long i=l;i<=r;i++)
#define rf(r,l) for(long long i=r;i>=l;i--)
#define made return
#define of 0
#define Barry +0
#define ll long long
using namespace std;
struct node{
	string s;
	ll sum;
};
queue<node>q;
ll n=1;
string A,B,a[1111],b[1111];
int main(){
	cin>>A>>B;
	while(cin>>a[n]>>b[n])
		n++;
	n--;
	q.push(node{A,0});
	while(!q.empty()){
		node u=q.front();
		q.pop();
		if(u.sum>=10)break;
		fr(1,n){
			int mark=u.s.find(a[i]);
			while(mark!=-1){
				string temp=u.s;
				temp=temp.replace(mark,a[i].size(),b[i]);
				if(temp==B){
					cout<<u.sum+1<<endl;
					return 0;
				}
				q.push(node{temp,u.sum+1});
				mark=u.s.find(a[i],mark+1); 
			}
		}
	}
	cout<<"NO ANSWER!"<<endl;
	made of Barry;
}

最短路径问题:

#include<bits/stdc++.h>
using namespace std;
#define N 2001
int a[105][2];
double d[105][105];
int main()
{
   int n,m;
   cin>>n;
   int i,j,k;
    memset(d,0x7f,sizeof(d));
   for(i=1;i<=n;i++)
   {
    cin>>a[i][1]>>a[i][2];
   }
   cin>>m;
   int x,y;
   for(i=1;i<=m;i++)//邻接矩阵
   {
       cin>>x>>y;
    d[x][y]=d[y][x]=sqrt(pow(double(a[x][1]-a[y][1]),2)+pow(double(a[x][2]-a[y][2]),2));
   }
 
 
   for(k=1;k<=n;k++)//floyed算法
    for(i=1;i<=n;i++)
    for(j=1;j<=n;j++)
    {
 
        if(i!=k&&j!=i&&j!=k&&d[i][j]>d[i][k]+d[k][j])
            d[i][j]=d[i][k]+d[k][j];
    }
    int b,e;
    cin>>b>>e;
    printf("%.2lf\n",d[b][e]);
   return 0;
}