暂存

约瑟夫环

#include <bits/stdc++.h>using namespace std;const int N = 1000 + 10;int main(){    int n, k;    scanf("%d%d", &n, &k);    int ans = 0;    for(int i = 2; i <= n; i++) ans = (ans + k) % i;    printf("%d\n", ans + 1);    return 0;}

染色

bool dfs(int v, int x){    color[v] = x;    for(int i = head[v]; ~i; i = g[i].next)    {        int u = g[i].to;        if(color[v] == color[u]) return false;        if(! color[u] && !dfs(u, -color[v])) return false;    }    return true;}bool bfs(int v, int x){    queue<int> que;    que.push(v), color[v] = x;    while(! que.empty())    {        int v = que.front(); que.pop();        for(int i = head[v]; ~i; i = g[i].next)        {            int u = g[i].to;            if(color[v] == color[u]) return false;            if(! color[u]) color[u] = -color[v], que.push(u);        }    }    return true;}

自造随机数（不会重复）

inline int random(){    static int seed=703; //seed可以随便取    return seed=int(seed*48271LL%2147483647);}