乱七八糟

// 八皇后
int ANS[8], y[8];
bool xie1[16], xie2[16];
int dfs(int line) {
    int ans = 0;
    if (line == 8) return 1;
    for (int i = 0 ; i < 8 ; i ++){
        if (y[i] || xie1[line - i + 7] || xie2[line + i]) continue;
        ANS[line] = i;
        y[i] = xie1[line - i + 7] = xie2[line + i] = true;
        ans += dfs(line + 1);
        y[i] = xie1[line - i + 7] = xie2[line + i] = false;
    }
    return ans;
}

// 边表
struct Edge{
    int to, value, pre;
    Edge(int _to, int _value, int _pre):to(_to), value(_value), pre(_pre){}
};
Edge edges[MAX << 1];
int edgePos;
int edgeHead;

void edgeInit() {
    int edgePos = 0;
    memset(edgeHead, -1, sizeof edgeHead);
}

void addEdge(int s, int to, int value) {
    edge[edgePos] = Edge(to, value, edgeHead[s]);
    edgeHead[s] = edgePos ++;
}