[POJ3264]Balanced Lineup（线段树，区间最值差）

题目链接：http://poj.org/problem?id=3264

写了一个更优美一点的

 1 #include <algorithm>
 2 #include <iostream>
 3 #include <iomanip>
 4 #include <cstring>
 5 #include <climits>
 6 #include <complex>
 7 #include <fstream>
 8 #include <cassert>
 9 #include <cstdio>
10 #include <bitset>
11 #include <vector>
12 #include <deque>
13 #include <queue>
14 #include <stack>
15 #include <ctime>
16 #include <set>
17 #include <map>
18 #include <cmath>
19
20 using namespace std;
21
22 #define fr first
23 #define sc second
24 #define pb(a) push_back(a)
25 #define Rint(a) scanf("%d", &a)
26 #define Rll(a) scanf("%I64d", &a)
27 #define Rs(a) scanf("%s", a)
28 #define FRead() freopen("in", "r", stdin)
29 #define FWrite() freopen("out", "w", stdout)
30 #define Rep(i, len) for(int i = 0; i < (len); i++)
31 #define For(i, a, len) for(int i = (a); i < (len); i++)
32 #define Cls(a) memset((a), 0, sizeof(a))
33 #define Full(a) memset((a), 0x7f7f, sizeof(a))
34
35 typedef struct Node {
36     int lo, hi;
37     Node() {}
38     Node(int l, int h) : lo(l), hi(h) {}
39 }Node;
40
41 #define lrt rt << 1
42 #define rrt rt << 1 | 1
43 const int maxn = 500010;
44 Node h[maxn<<1];
45 int n, q;
46
47 void pushUP(int rt) {
48     h[rt].lo = min(h[lrt].lo, h[rrt].lo);
49     h[rt].hi = max(h[lrt].hi, h[rrt].hi);
50 }
51
52 void build(int l, int r, int rt) {
53     if(l == r) {
54         Rint(h[rt].lo);
55         h[rt].hi = h[rt].lo;
56         return;
57     }
58     int m = (l + r) >> 1;
59     build(l, m, lrt);
60     build(m+1, r, rrt);
61     pushUP(rt);
62 }
63
64 Node query(int L, int R, int l, int r, int rt) {
65     if(L <= l && r <= R) return h[rt];
66     int m = (l + r) >> 1;
67     Node ret(0x7f7f7f, 0), tmp;
68     if(m >= L) {
69         tmp = query(L, R, l, m, lrt);
70         ret.lo = min(ret.lo, tmp.lo);
71         ret.hi = max(ret.hi, tmp.hi);
72     }
73     if(m < R) {
74         tmp = query(L, R, m+1, r, rrt);
75         ret.lo = min(ret.lo, tmp.lo);
76         ret.hi = max(ret.hi, tmp.hi);
77     }
78     return ret;
79 }
80
81 int main() {
82     // FRead();
83     int a, b;
84     while(~Rint(n) && ~Rint(q)) {
85         build(1, n, 1);
86         while(q--) {
87             Rint(a); Rint(b);
88             Node ret = query(a, b, 1, n, 1);
89             printf("%d\n", ret.hi - ret.lo);
90         }
91     }
92     return 0;
93 }