【狀態壓縮DP】HDU 2167

跟POJ 1185炮兵陣地差不多

int g[16][16];int st[1001];char str[101];int dp[16][(1<<15)];int num[16][1001];int n;int tot;bool ok(int x){    if(x & (x<<1))return 0;    if(x & (x>>1))return 0;    return 1;}void init(){    tot = 0;    int i;    for(i=0;i<(1<<n);i++){        if(ok(i)){            st[tot++] = i;        }    }}int cal(int x,int y){    int res = 0;    int i,j;    int m = st[y];    int cnt =0 ;    while(m){        if(m&1)res += g[x][cnt];        cnt++;        m>>=1;    }    return res;}void gao(){    memset(dp,0,sizeof(dp));    int i,j,k;    for(i=0;i<n;i++){        for(j=0;j<tot;j++){            if(!i){dp[i][j] = num[i][j];continue;}            for(k=0;k<tot;k++){                if(st[j] & st[k])continue;                if(st[j] & (st[k]<<1))continue;                if(st[j] & (st[k]>>1))continue;                dp[i][j] = max(dp[i][j], dp[i-1][k]+num[i][j]);            }        }    }    int ans = 0;    for(i=0;i<tot;i++){        ans = max(ans,dp[n-1][i]);    }    printf("%d\n",ans);}int main(){    int i = 0,j;    while(gets(str)){        n = 0;        int sum = 0;        for(i=0;str[i];i++){            if(str[i]==' '){                g[0][n++] = sum;                sum = 0;            } else {                sum = sum*10+str[i]-'0';            }        }        g[0][n++] = sum;        for(i=1;i<n;i++){            gets(str);            int m = 0;            sum =0 ;            for(j=0;str[j];j++){                if(str[j]==' '){                    g[i][m++] = sum;                    sum =0 ;                } else {                    sum = sum*10+str[j]-'0';                }            }            g[i][m++] = sum;        }        init();        for(i=0;i<n;i++){            for(j=0;j<tot;j++){                num[i][j] = cal(i,j);            }        }        gao();        getchar();    }    return 0;}