RMQ模版

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ST

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]);
}

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]);
					else
						dp[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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RMQ模版

标签：class   blog   c   code   a   int   

原文地址：http://blog.csdn.net/u011686226/article/details/26860375