HDU 5443 The Water Problem （水题，暴力）

题意：给定 n 个数，然后有 q 个询问，问你每个区间的最大值。

析：数据很小，直接暴力即可，不会超时，也可以用RMQ算法。

代码如下：

#include <cstdio>
#include <string>
#include <cstdlib>
#include <cmath>
#include <iostream>
#include <cstring>
#include <set>
#include <queue>
#include <algorithm>
#include <vector>
#include <map>
#include <cctype>
using namespace std ;
typedef long long LL;
typedef pair<int, int> P;
const int INF = 0x3f3f3f3f;
const double inf = 0x3f3f3f3f3f3f3f;
const double eps = 1e-8;
const int maxn = 1e3 + 5;
const int dr[] = {0, 0, -1, 1};
const int dc[] = {-1, 1, 0, 0};
int n, m;
inline bool is_in(int r, int c){
    return r >= 0 && r < n && c >= 0 && c < m;
}
int a[maxn];
int main(){
    int T;
    cin >> T;
    while(T--){
        scanf("%d", &n);
        for(int i = 1; i <= n; ++i)  scanf("%d", &a[i]);
        scanf("%d", &m);
        while(m--){
            int l, r;
            scanf("%d %d", &l, &r);
            int ans = -1;
            for(int i = l; i <= r; ++i)
                ans = max(ans, a[i]);
            printf("%d\n", ans);
        }
    }
    return 0;
}

　　

#include <cstdio>
#include <string>
#include <cstdlib>
#include <cmath>
#include <iostream>
#include <cstring>
#include <set>
#include <queue>
#include <algorithm>
#include <vector>
#include <map>
#include <cctype>
using namespace std ;
typedef long long LL;
typedef pair<int, int> P;
const int INF = 0x3f3f3f3f;
const double inf = 0x3f3f3f3f3f3f3f3f;
const double eps = 1e-8;
const int maxn = 1e3 + 5;
const int dr[] = {0, 0, -1, 1};
const int dc[] = {-1, 1, 0, 0};
int n, m;
inline bool is_in(int r, int c){
    return r >= 0 && r < n && c >= 0 && c < m;
}
int d[maxn][20];

void rmq_init(){
    for(int j = 1; (1<<j) <= n; ++j)
        for(int i = 1; i + (1<<j) - 1 <= n; ++i)
            d[i][j] = max(d[i][j-1], d[i+(1<<(j-1))][j-1]);
}

int rmq_query(int l, int r){
    //int k = log(r-l+1)/log(2.0);
    int k = 0;
    while((1<<(k+1)) <= r-l+1)  ++k;
    return max(d[l][k], d[r-(1<<k)+1][k]);
}

int main(){
    int T;  cin >> T;
    while(T--){
        scanf("%d", &n);
        memset(d, 0, sizeof(d));
        for(int i = 0; i < n; ++i)
            scanf("%d", &d[i+1][0]);
        rmq_init();
        scanf("%d", &m);
        while(m--){
            int l, r;
            scanf("%d %d", &l, &r);
            printf("%d\n", rmq_query(l, r));
        }
    }
    return 0;
}