poj1659 Frogs' Neighborhood(havel算法)

实质就是贪心，从度数大的开始。

struct node {    int deg;    int id;    bool operator < (const node& rhs) const {        return deg > rhs.deg;    }}p[11];int mp[11][11];void solve(int n) {    bool flag = true;    memset(mp, 0, sizeof mp);    int m = n;    while(m--) {        sort(p, p + n);        int _count = p[0].deg;        if (_count <= 0) break;        if (_count >= n) {            flag = false;            break;        }        for (int i = 1;i <= _count;++i) {            p[i].deg--;            mp[p[0].id][p[i].id] = mp[p[i].id][p[0].id] = 1;            if (p[i].deg < 0) {                flag = false;            }        }        p[0].deg = 0;    }    if (!flag) puts("NO");    else {        puts("YES");        for (int i = 0;i < n;++i) {            for (int j = 0;j < n;++j)                printf("%d%c", mp[i][j], j == n - 1?'\n':' ');        }    }}int main(int argc, const char * argv[]){        // freopen("in.txt","r",stdin);    // freopen("out.txt","w",stdout);    // clock_t _ = clock();    int t, n;    cin >> t;    while(t--) {        scanf("%d", &n);        for (int i = 0;i < n;++i)            cin >> p[i].deg, p[i].id = i;        solve(n);        if (t) puts("");    }        // printf("\nTime cost: %.2fs\n", 1.0 * (clock() - _) / CLOCKS_PER_SEC);    return 0;}