Problem Description
In Land waterless, water is a very limited resource. People always fight for the biggest source of water. Given a sequence of water sources with a1,a2,a3,...,anrepresenting the size of the water source. Given a set of queries each containing 2 integers l and r, please find out the biggest water source between al and ar.
Input
First you are given an integer T(T≤10) indicating the number of test cases. For each test case, there is a number n(0≤n≤1000) on a line representing the number of water sources. n integers follow, respectively a1,a2,a3,...,an, and each integer is in { 1,...,106}. On the next line, there is a number q(0≤q≤1000) representing the number of queries. After that, there will be q lines with two integers l and r(1≤l≤r≤n) indicating the range of which you should find out the biggest water source.
Output
For each query, output an integer representing the size of the biggest water source.
Sample Input
3
110011 151 2 3 4 551 21 32 43 43 531 999999 141 11 22 33 3 Sample Output
100
2
3
4
4
5
1
999999
999999
1
区间最大值 线段树
#include#include #include #include #include using namespace std;const int oo = 0x3f3f3f3f;const int N = 1005;typedef long long LL;struct da{ int left, right, val;}as[N*4];int n, ac[N];void build(int left, int right, int i){ as[i].left = left; as[i].right = right; int mid = (left + right)/2; if(left == right) { as[i].val = ac[left]; return ; } build(left, mid, 2*i); build(mid+1, right, 2*i+1); as[i].val = max(as[i*2].val, as[2*i+1].val);}void query(int left, int right, int i, int &ans){ if(as[i].left == left && as[i].right == right) { ans = max(as[i].val, ans); return ; } int mid = (as[i].left + as[i].right)/2; if(right <= mid) query(left, right, 2*i, ans); else if(left > mid) query(left, right, 2*i+1, ans); else { query(left, mid, 2*i, ans); query(mid+1, right, 2*i+1, ans); }}int main(){ int T, Q; scanf("%d", &T); while(T--) { scanf("%d", &n); for(int i = 1; i <= n; i++) scanf("%d", &ac[i]); build(1, n, 1); scanf("%d", &Q); while(Q--) { int a, b; scanf("%d %d", &a, &b); int ans = 0; query(a, b, 1, ans); printf("%d\n", ans); } } return 0;}