[leetcode] 最多可达成的换楼请求数目 暴力水题

class Solution {
public:
    int maximumRequests(int n, vector<vector<int>>& requests) {
        int cnt[21];
        int len = requests.size();
        int lim = (1 << len);
        int ans = 0;
        for(int i = 0;i < lim;i ++) {
            int t = i;
            int pos = 0;
            int tans = 0;
            while(t) {
                ++ pos;
                int x = requests[pos - 1][0], y = requests[pos - 1][1];
                if(t & 1) cnt[x] --,cnt[y] ++, tans ++;
                t >>= 1;
            }
            int flag = 0;
            for(int i = 0;i < n;i ++) {
                if(cnt[i]) {
                    flag = 1;
                    cnt[i] = 0;
                }
            }
            if(flag == 0) ans = max(ans, tans);
        }
        return ans;
    }
};