http://poj.org/problem?id=3264
给定一个50000的数组，200000次查询，每次查询求区间的最大值与最小值之差
明显的线段树的版题，维护区间最大值和最小值
第一道线段树的题目！
1 // #pragma comment(linker, "/STACK:102400000,102400000") 2 #include <cstdio> 3 #include <iostream> 4 #include <cstring> 5 #include <string> 6 #include <cmath> 7 #include <set> 8 #include <list> 9 #include <map> 10 #include <iterator> 11 #include <cstdlib> 12 #include <vector> 13 #include <queue> 14 #include <stack> 15 #include <algorithm> 16 #include <functional> 17 using namespace std; 18 typedef long long LL; 19 #define ROUND(x) round(x) 20 #define FLOOR(x) floor(x) 21 #define CEIL(x) ceil(x) 22 const int maxn = 100010; 23 const int maxm = 0; 24 const int inf = 0x3f3f3f3f; 25 const LL inf64 = 0x3f3f3f3f3f3f3f3fLL; 26 const double INF = 1e30; 27 const double eps = 1e-6; 28 int N, Q; 29 int n; 30 int seq[maxn]; 31 struct Node 32 { 33 int l, r; 34 int ll, rr; 35 int minx; 36 int maxx; 37 Node(int _l = -1, int _r = -1, int _ll = -1, int _rr = -1, int _minx = -1, int _maxx = -1): l(_l), r(_r), ll(_ll), rr(_rr), minx(_minx), maxx(_maxx) {} 38 }; 39 Node node[maxn * 10]; 40 void init() 41 { 42 n = 0; 43 } 44 void input() 45 { 46 scanf("%d%d", &N, &Q); 47 for (int i = 1; i <= N; i++) 48 { 49 scanf("%d", &seq[i]); 50 } 51 } 52 void debug() 53 { 54 cout << node[6].minx << " " << node[6].maxx << endl; 55 cout << node[8].minx << " " << node[8].maxx << endl; 56 } 57 int getmin(int l, int r, int fa) 58 { 59 if (l == node[fa].l && r == node[fa].r) return node[fa].minx; 60 int m = (node[fa].l + node[fa].r) >> 1; 61 int ret = inf; 62 if (r <= m) 63 { 64 ret = min(ret, getmin(l, r, node[fa].ll)); 65 } 66 else if (l > m) 67 { 68 ret = min(ret, getmin(l, r, node[fa].rr)); 69 } 70 else 71 { 72 ret = min(ret, getmin(l, m, node[fa].ll)); 73 ret = min(ret, getmin(m + 1, r, node[fa].rr)); 74 } 75 return ret; 76 } 77 int getmax(int l, int r, int fa) 78 { 79 if (l == node[fa].l && r == node[fa].r) return node[fa].maxx; 80 int m = (node[fa].l + node[fa].r) >> 1; 81 int ret = 0; 82 if (r <= m) 83 { 84 ret = max(ret, getmax(l, r, node[fa].ll)); 85 } 86 else if (l > m) 87 { 88 ret = max(ret, getmax(l, r, node[fa].rr)); 89 } 90 else 91 { 92 ret = max(ret, getmax(l, m, node[fa].ll)); 93 ret = max(ret, getmax(m + 1, r, node[fa].rr)); 94 } 95 return ret; 96 } 97 int build(int l, int r) 98 { 99 int now = n; 100 n++; 101 node[now] = Node(l, r, -1, -1, -1, -1); 102 if (l == r) 103 { 104 node[now].minx = min(seq[l], seq[r]); 105 node[now].maxx = max(seq[l], seq[r]); 106 return now; 107 } 108 int m = (l + r) >> 1; 109 node[now].ll = build(l, m); 110 node[now].rr = build(m + 1, r); 111 node[now].minx = min(node[node[now].ll].minx, node[node[now].rr].minx); 112 node[now].maxx = max(node[node[now].ll].maxx, node[node[now].rr].maxx); 113 return now; 114 } 115 void solve() 116 { 117 build(1, N); 118 while (Q--) 119 { 120 int l, r; 121 scanf("%d%d", &l, &r); 122 printf("%d ", getmax(l, r, 0) - getmin(l, r, 0)); 123 } 124 } 125 void output() 126 { 127 // 128 } 129 int main() 130 { 131 // std::ios_base::sync_with_stdio(false); 132 // #ifndef ONLINE_JUDGE 133 // freopen("in.cpp", "r", stdin); 134 // #endif 135 136 init(); 137 input(); 138 solve(); 139 output(); 140 return 0; 141 }