【UOJ #147】【NOIP 2015】斗地主

http://uoj.ac/problem/147

搜索时先枚举三顺子，双顺子和单顺子，然后贪心带牌和成三成双成单出。

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int in() {
	int k = 0, fh = 1; char c = getchar();
	for(; c < '0' || c > '9'; c = getchar())
		if (c == '-') fh = -1;
	for(; c >= '0' && c <= '9'; c = getchar())
		k = (k << 3) + (k << 1) + c - '0';
	return k * fh;
}


int a[20], c[5], n, ans;

int cal() {
	memset(c, 0, sizeof(c));
	for(int i = 0; i <= 13; ++i)
		++c[a[i]];
	int ret = 0;
	while (c[4] && c[2] >= 2) --c[4], c[2] -= 2, ++ret;
	while (c[4] && c[1] >= 2) --c[4], c[1] -= 2, ++ret;
	while (c[3] && c[2]) --c[3], --c[2], ++ret;
	while (c[3] && c[1]) --c[3], --c[1], ++ret;
	return ret + c[4] + c[3] + c[2] + c[1];
}

void dfs(int step) {
	if (step >= ans) return;
	ans = min(ans, step + cal());
	
	int i, j, k, tail;
	j = 0;
	for(i = 2; i <= 13; ++i) {
		for(j = max(j, i); a[j] >= 3; ++j);
		for(tail = j; tail >= i + 2; --tail) {
			for(k = i; k < tail; ++k) a[k] -= 3;
			dfs(step + 1);
			for(k = i; k < tail; ++k) a[k] += 3;
		}
	}
	
	j = 0;
	for(i = 2; i <= 13; ++i) {
		for(j = max(j, i); a[j] >= 2; ++j);
		for(tail = j; tail >= i + 3; --tail) {
			for(k = i; k < tail; ++k) a[k] -= 2;
			dfs(step + 1);
			for(k = i; k < tail; ++k) a[k] += 2;
		}
	}
	
	j = 0;
	for(int i = 2; i <= 13; ++i) {
		for(j = max(j, i); a[j] >= 1; ++j);
		for(tail = j; tail >= i + 5; --tail) {
			for(k = i; k < tail; ++k) --a[k];
			dfs(step + 1);
			for(k = i; k < tail; ++k) ++a[k];
		}
	}
}

int main() {
	int T, color, num; T = in(); n = in();
	while (T--) {
		memset(a, 0, sizeof(a));
		for(int i = 1; i <= n; ++i) {
			num = in(); color = in();
			if (num == 1) num = 13;
			else if (num != 0) --num;
			++a[num];
		}
		ans = cal();
		dfs(0);
		printf("%d\n", ans);
	}
	return 0;
}

QAQ