快读

inline bool isdigit_(char x){
    return (x >= '0' && x <= '9') ? true : false;
}
namespace fast_IO {
    const int IN_LEN = 100000 , OUT_LEN = 100000;
    char ibuf[IN_LEN] , obuf[OUT_LEN] , *ih = ibuf + IN_LEN , *oh = obuf , *lastin = ibuf + IN_LEN , *lastout = obuf + OUT_LEN - 1;
    inline char getchar_() {
        return (ih == lastin) && (lastin = (ih = ibuf) + fread(ibuf , 1 , IN_LEN , stdin) , ih == lastin) ? EOF : *ih ++;
    }
}
using namespace fast_IO;
inline int read(){
    register int x = 0;
    char c = getchar_() ; c = getchar_();
    while(isdigit_(c)){
        x = (x << 1) + (x << 3) + (c ^ 48);
        c = getchar_();
    }
    return x;
}

$dijkstra:$

void dijkstra(int s){
	memset(dis , 0x3f , sizeof dis);
	memset(vis , 0 , sizeof vis);
	priority_queue < Node > q;
	q . push({s , dis[s]});
	while(! q . empty()){
		int u = q . top() . u ; q . pop();
		if(vis[u] == 1) continue;
		vis[u] = 1;
		for(int i = head[u] ; i ; i = e[i] . nxt){
			int v = e[i] . to , w = e[i] . w;
			if(dis[v] > dis[u] + e[i] . w){
				dis[v] = dis[u] + e[i] . w;
				q . push({v , dis[v]});
			}
		}
	}
}

$spfa$

void spfa () {
	memset(dis , 0x3f , sizeof dis);
	queue < int > q;
	q . push(bx);
	vis[bx] = 1 , dis[bx] = 0;
	while (! q . empty()) {
		int u = q . front() ; q . pop();
		vis[u] = 0;
		for (int i = head[u] ; i ; i = e[i] . nxt) {
			int v = e[i] . to;
			if (dis[v] > dis[u] + e[i] . w) {
				dis[v] = dis[u] + e[i] . w;
				if (! vis[v]) vis[v] = 1 , q . push(v);
			}
		}
	}
}

并查集

int find(int x){
	if(f[x] == x) return x;
	return f[x] = find(f[x]);
}

int merge(int x , int y){
  x = find(x) , y = find(y);
  f[x] = y;
}

$Kruscal$

bool cmp(Edge x , Edge y){
	return x . w < y . w;
}
void Kruscal(){
	sort(E + 1 , E + m + 1 , cmp);
	for(int i = 1 ; i <= m ; i++){
		int x = find(E[i] . from) , y = find(E[i] . to);
		if(x == y) continue ; f[x] = y;
		if(++ total >= n - 1) return;
	}
}

$Toposort:$

void toposort(){
	queue < int > q;
	for(int i = 1 ; i <= n ; i ++) 
		if(du[i] == 0) q . push(i);
	while(! q . empty()){
		int v = q . front() ; q . pop();
		for(int u : G[v]){
			du[u] -- ; 
			if(du[u] <= 0) q . push(u);
		}
	}
}

快速幂

#define mod 998244353
#define int long long
int quick_pow(int x , int y){
	if(y == 0) return 1;
	int a = quick_pow(x , y / 2);
	if(y % 2 == 0) return (a * a) % mod;
	else return (a * a * x) % mod;
}

线性筛

int O_n_prime(){
	for(int i = 2 ; i <= n ; i ++){
		if(isPrime[i] == 0) prime . push_back(i);
		for(int j = 0 ; j < prime() . size() ; j ++){
			isPrime[i * prime[j]] = 1;
			if(i % prime[j] == 0) break;
		}
	}
}

$vector$

vector < int > v[100005];
if(a[i] > n) continue;
pos[a[i]] . push_back(i);
int x , y ; cin >> x >> y;
//二分下标
idx = () , idy = ();
cout << idy - idx + 1 << endl;

单调队列

while(hd <= ed && dq[ed] . sum > tmp) -- ed;
dq[++ ed] = {i , tmp};
while(i - dq[hd] . t >= m) ++ hd;