The Great Mixing

这道题非常有意思

#include <iostream>#include <cstring>#include <cstdio>#include <queue>#include <vector>#define inf 0x3f3f3f3fusing namespace std;int a[2234];int dp[5005];int n, k;int vis[5005];vector<int>v;int bfs() {    int i, sum = 0;    queue<int>q;    for (i = 0; i < v.size(); i++) {        int m = v[i] + 1000;        if(vis[m]==0){        q.push(m);        vis[m]=1;        dp[m] = 1;        }        if(m==1000) return 1;    }    int temp;    while (!q.empty()) {        temp = q.front();        q.pop();        for (i = 0; i < v.size(); i++) {            sum = temp + v[i];            if (dp[sum]>dp[temp] + 1 && sum <= 2000 && sum >= 0){                dp[sum] = dp[temp] + 1;            if (sum == 1000)return 1;            if (vis[sum] == 0) {                q.push(sum);                vis[sum] = 1;            }            }        }    }    return -1;}int main(){    memset(a, 0, sizeof(a));    memset(dp, inf, sizeof(dp));    cin >> n >> k;    int i, t;    for (i = 1; i <= k; i++) {        scanf("%d",&t);        if(a[t-n+1000]==0){            v.push_back(t-n);        }        a[t-n+1000] = 1;    }    bfs();    if (dp[1000] != inf)        cout << dp[1000] << endl;    else cout << -1 << endl;    return 0;}