RMQ模版

来源：互联网发布：阿里云备案空间多少钱编辑：程序博客网时间：2024/05/21 06:40

int dp[maxn][20];int a[maxn];void RMQ_init(int n){int i,j,k;for(i = 1; i <= n; i++)dp[i][0] = a[i];k = (int) (log((double)n + 0.2) / log(2.0));for(j = 1; j <= k; j++)for(i = 1; i + (1 << j) - 1 <= n; i++)dp[i][j] = min(dp[i][j-1], dp[i + (1 << (j-1))][j-1]);}

二维ST

void RMQ_init(int n){for(int i = 1; i <= n; i++)for(int j = 1; j <= n; j++){dp[i][j][0][0] = a[i][j];}int k = (int) (log((double)n + 0.2) / log(2.0));for(int x = 0; x <= k; x++)for(int y = 0; y <= k; y++){if(!x && !y)continue;for(int i = 0; i + (1<<x) - 1 <= n; i++)for(int j = 0; j + (1<<y) - 1 <= n; j++){if(x == 0)dp[i][j][x][y] = max(dp[i][j][x][y-1], dp[i][j+(1<<(y-1))][x][y-1]);elsedp[i][j][x][y] = max(dp[i][j][x-1][y], dp[i+(1<<(x-1))][j][x-1][y]);}}}int RMQ(int x1, int y1, int x2, int y2){int kx = log(double(x2 - x1 + 1)) / log(2.0);int ky = log(double(y2 - y1 + 1)) / log(2.0);int ans = 0;ans = max(ans, dp[x1][y1][kx][ky]);ans = max(ans, dp[x2-(1<<kx)+1][y1][kx][ky]);ans = max(ans, dp[x1][y2-(1<<ky)+1][kx][ky]);ans = max(ans, dp[x2-(1<<kx)+1][y2-(1<<ky)+1][kx][ky]);return ans;}

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