tyvj 1684（状态压缩dp）

#include <iostream>#include <cstdio>#include <cstring>using namespace std;int n, m, p;int Map[110];int dp[110][65][65];int s[110], num[110];inline int max(int a, int b) {return a > b ? a : b;}bool check(int x) {if(x & (x >> 1))return false;if(x & (x >> 2))return false;return true;}int Count(int x) {int i = 1, ans = 0;while(i <= x) {if(x & i)ans++;i <<= 1;}return ans;}void Init() {int i;p = 0;memset(s, 0, sizeof(s));memset(num, 0, sizeof(num));for(i = 0; i < (1 << m); i++) {if(check(i)) {s[p] = i;num[p++] = Count(i);}}}int main() {char ch;int i, k, j, r, total;scanf("%d%d", &n, &m);if(!n && !m) {printf("0\n");return 0;}memset(dp, 0, sizeof(dp));memset(Map, 0, sizeof(Map));for(i = 0; i < n; i++)for(j = 0; j < m; j++) {cin >> ch;if(ch == 'X')Map[i] = Map[i] | (1 << (m - 1 - j));}Init();for(i = 0; i < p; i++)if(!(Map[0] & s[i]))dp[0][i][0] = num[i];for(i = 0; i < p; i++) {if(!(Map[1] & s[i])) {for(j = 0; j < p; j++) {if(!(s[i] & s[j]))dp[1][i][j] = max(dp[1][i][j], dp[0][j][0] + num[i]);}}}for(r = 2; r < n; r++)for(i = 0; i < p; i++)if(!(s[i] & Map[r]))for(j = 0; j < p; j++)if(!(s[j] & Map[r - 1]) && !(s[i] & s[j]))for(k = 0; k < p; k++)if(!(s[k] & Map[r - 2]) && !(s[k] & s[j]) && !(s[k] & s[i]))dp[r][i][j] = max(dp[r][i][j], dp[r - 1][j][k] + num[i]);int ans = 0;for(i = 0; i < p; i ++)for(j = 0; j < p; j++)ans = max(ans, dp[n - 1][i][j]);printf("%d\n", ans);return 0;}

状态压缩dp