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  • RMQ模板

    void RMQ_init()
    {
        for(int i=1; i<=n; i++) dp[i][0]=s[i];
        for(int j=1; (1<<j)<=n; j++)
            for(int i=1;i+(1<<j)-1<=n;i++)
                dp[i][j]=max(dp[i][j-1],dp[i+(1<<(j-1))][j-1]);
    }
    int RMQ(int L,int R)
    {
        int k=0;
        while((1<<(k+1))<=R-L+1) k++;
        return max(dp[L][k],dp[R-(1<<k)+1][k]);
    }
    

      

    附带讲解:

    http://blog.csdn.net/liang5630/article/details/7917702

    #include <cstring>
    #include <cmath>
    #include <cstdio>
    #include <algorithm>
    #define N 50010
    using namespace std;
    
    int maxArr[N][16], minArr[N][16];
    int n, q, num[N];
    
    void Sparse_Table(){
    	int l = (int)(log((double)n) / log(2.0));
    	for (int j = 1;j <= l;j++)
    		for (int i = 1; i + (1 << (j - 1) ) - 1 <= n;++i){
    			maxArr[i][j] = max(maxArr[i][j - 1], maxArr[i + (1 << (j - 1))][j - 1]);
    			minArr[i][j] = min(minArr[i][j - 1], minArr[i + (1 << (j - 1))][j - 1]);
    		}
    }
    
    int rmq(int l, int r){
    	int k = (int)(log((double)(r - l + 1)) / log(2.0));
    	int Max = max(maxArr[l][k], maxArr[r - (1 << k) + 1][k]);
    	int Min = min(minArr[l][k], minArr[r - (1 << k) + 1][k]);
    	return Max - Min;
    }
    
    int main(){
    	while (~scanf("%d %d", &n, &q)){
    		memset(maxArr, 0, sizeof(maxArr));
    		memset(minArr, 0, sizeof(minArr));
    		for (int i = 1;i <= n;i++){
    			scanf("%d", &num[i]);
    			maxArr[i][0] = minArr[i][0] = num[i];
    		}
    		Sparse_Table();
    		int l, r;
    		while (q--){
    			scanf("%d%d", &l, &r);
    			printf("%d
    ", rmq(l, r));
    		}
    	}
    	return 0;
    }
    

      

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  • 原文地址:https://www.cnblogs.com/boson-is-god/p/5878059.html
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