【DP】 POJ 1085 Triangle War

状态用二进制压缩存储，然后记忆化搜索就可以了。。。

#include <iostream>#include <queue> #include <stack> #include <map> #include <set> #include <bitset> #include <cstdio> #include <algorithm> #include <cstring> #include <climits>#include <cstdlib>#include <cmath>#include <time.h>#define maxn 300005#define maxm 400005#define eps 1e-7#define mod 1000000007#define INF 0x3f3f3f3f#define PI (acos(-1.0))#define lowbit(x) (x&(-x))#define mp make_pair#define ls o<<1#define rs o<<1 | 1#define lson o<<1, L, mid #define rson o<<1 | 1, mid+1, R#define pii pair<int, int>#pragma comment(linker, "/STACK:16777216")typedef long long LL;typedef unsigned long long ULL;//typedef int LL;using namespace std;LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}// headint o = (1 << 18) - 1;int dp[maxn][2];int a[maxn];int c[maxn];int m, s, ss, res;void init(){a[0] = (1 << 0) | (1 << 1) | (1 << 2);a[1] = (1 << 3) | (1 << 4) | (1 << 7);a[2] = (1 << 4) | (1 << 5) | (1 << 2);a[3] = (1 << 5) | (1 << 6) | (1 << 8);a[4] = (1 << 9) | (1 << 10) | (1 << 15);a[5] = (1 << 7) | (1 << 10) | (1 << 11);a[6] = (1 << 11) | (1 << 12) | (1 << 16);a[7] = (1 << 12) | (1 << 13) | (1 << 8);a[8] = (1 << 13) | (1 << 14) | (1 << 17);a[9] = (1 << 0) | (1 << 3) | (1 << 1) | (1 << 6) | (1 << 7) | (1 << 8);for(int i = 0; i <= o; i++)for(int j = 0; j < 9; j++)if((i & a[j]) == a[j]) c[i]++;memset(dp, INF, sizeof dp);}void read(){scanf("%d", &m);res = ss = 0;int t = 0, aa, bb, t2 = 0;for(int i = 0; i < m; i++) {scanf("%d%d", &aa, &bb);if(aa > bb) swap(aa, bb);if(aa == 1) {if(bb == 2) t |= (1 << 0);if(bb == 3) t |= (1 << 1);}if(aa == 2) {if(bb == 3) t |= (1 << 2);if(bb == 4) t |= (1 << 3);if(bb == 5) t |= (1 << 4);}if(aa == 3) {if(bb == 5) t |= (1 << 5);if(bb == 6) t |= (1 << 6);}if(aa == 4) {if(bb == 5) t |= (1 << 7);if(bb == 7) t |= (1 << 9);if(bb == 8) t |= (1 << 10);}if(aa == 5) {if(bb == 6) t |= (1 << 8);if(bb == 8) t |= (1 << 11);if(bb == 9) t |= (1 << 12);}if(aa == 6) {if(bb == 9) t |= (1 << 13);if(bb == 10) t |= (1 << 14);}if(aa == 7) t |= (1 << 15);if(aa == 8) t |= (1 << 16);if(aa == 9) t |= (1 << 17);if(!ss) res += c[t] - c[t2];else res -= c[t] - c[t2];if(!(c[t] - c[t2])) ss ^= 1;t2 = t;}s = t;}int dfs(int now, bool flag){if(dp[now][flag] != INF) return dp[now][flag];if(now == o) return dp[now][flag] = 0;int ans;if(flag) ans = -INF;else ans = INF;for(int i = 0; i < 18; i++) {if((now & (1 << i)) == (1 << i)) continue;int next = now | (1 << i);if(c[next] == c[now]) {if(flag) ans = max(ans, dfs(next, 0));else ans = min(ans, dfs(next, 1));}else {if(flag) ans = max(ans, dfs(next, 1) + c[next] - c[now]);else ans = min(ans, dfs(next, 0) - (c[next] - c[now]));}}return dp[now][flag] = ans;}void work(){res += dfs(s, ss ^ 1);if(res > 0) printf("A wins.\n");else printf("B wins.\n");}int main(){init();int _, __ = 0;while(scanf("%d", &_)!=EOF) {__ = 0;while(_--) {read();printf("Game %d: ", ++__);work();}}return 0;}