【2005-2006 ACM-ICPC, NEERC, Moscow Subregional Contest】Problem J. Jack-pot

简单dfs，差分一下A数组和建出字典树能写得更方便，若不这么做代码时就会像我一样难受。

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
typedef long long ll;

const int N = 100003;

int a[13][N], n, m, k, A[13], pos[13][N];

ll dfs(int tmp, int l, int r, int f) {
	if (tmp > m) {
		return 1ll * (r - l + 1) * A[m];
	}
	
	int und = l;
	ll ans = 1000000000000000ll;
	if (r - l + 1 < k || (a[tmp][l] != 0) || (a[tmp][r] != k - 1)) {
		ans = 1ll * A[tmp - 1] * (r - l + 1);
		if (a[tmp][l] != 0) pos[tmp - 1][f] = 0;
		if (a[tmp][r] != k - 1) pos[tmp - 1][f] = -(k - 1);
	}
	for (int i = l + 1; i <= r; ++i)
		if (a[tmp][i] != a[tmp][i - 1] && a[tmp][i] != a[tmp][i - 1] + 1) {
			ans = 1ll * A[tmp - 1] * (r - l + 1);
			pos[tmp - 1][f] = -(a[tmp][i - 1] + 1);
			break;
		}
	
	for (int i = l + 1; i <= r + 1; ++i)
		if (i > r || a[tmp][i] != a[tmp][und]) {
			int num = dfs(tmp + 1, und, i - 1, und) + 1ll * A[tmp - 1] * (r - l + 1 - (i - und));
			if (num < ans) {
				ans = num;
				pos[tmp - 1][f] = und;
			}
			
			und = i;
		}
	return ans;
}

char s[13];

int main() {
	scanf("%d%d%d", &n, &m, &k);
	for (int i = 1; i <= m; ++i) scanf("%d", &A[i]);
	for (int i = 1; i <= n; ++i) {
		scanf("%s", s + 1);
		for (int j = 1; j <= m; ++j)
			a[j][i] = s[j] - '0';
	}
	ll ans = dfs(1, 1, n, 1); int tmp = 1;
	for (int i = 1; i <= m; ++i) {
		tmp = pos[i - 1][tmp];
		if (tmp <= 0) {
			printf("%d", -tmp);
			for (int j = i + 1; j <= m; ++j) putchar('0');
			break;
		}
		printf("%d", a[i][tmp]);
	}
	printf("
%lld
", ans);
	return 0;
}