【POJ】2528 Mayor's posters

离散化+线段树。
数组开的不够大，wa了N多回。

  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <algorithm>
  5 using namespace std;
  6 
  7 #define MAXN 12010
  8 #define lson l, mid, rt<<1
  9 #define rson mid+1, r, rt<<1|1
 10 
 11 int ls[MAXN], rs[MAXN];
 12 int nums[MAXN<<4];
 13 int buf[MAXN*3], cnt;
 14 char set[MAXN];
 15 
 16 inline int bin(int x, int n) {
 17     int l = 0, r = n-1;
 18     int mid;
 19 
 20     while (l <= r) {
 21         mid = (l+r)>>1;
 22         if (buf[mid] == x)
 23             return mid;
 24         if (buf[mid] < x)
 25             l = mid+1;
 26         else
 27             r = mid-1;
 28     }
 29 
 30     return -1;
 31 }
 32 /*
 33 void build(int l, int r, int rt) {
 34     nums[rt] = 0;
 35     if (l == r)
 36         return ;
 37     int mid = (l+r)>>1;
 38     build(lson);
 39     build(rson);
 40 }*/
 41 
 42 inline void PushDown(int rt) {
 43     if ( nums[rt] ) {
 44         nums[rt<<1] = nums[rt<<1|1] = nums[rt];
 45         nums[rt] = 0;
 46     }
 47 }
 48 
 49 void update(int ll, int rr, int c, int l, int r, int rt) {
 50     if (ll<=l && rr>=r) {
 51         nums[rt] = c;
 52         return ;
 53     }
 54     PushDown(rt);
 55     int mid = (l+r)>>1;
 56     if (ll <= mid)
 57         update(ll, rr, c, lson);
 58     if (rr > mid)
 59         update(ll, rr, c, rson);
 60 }
 61 
 62 void query(int l, int r, int rt) {
 63     if ( nums[rt] ) {
 64         if ( !set[nums[rt]] )
 65             ++cnt;
 66         set[nums[rt]] = 1;
 67         return ;
 68     }
 69     if (l == r)
 70         return ;
 71     int mid = (l+r)>>1;
 72     query(lson);
 73     query(rson);
 74 }
 75 
 76 int main() {
 77     int case_n, n, m;
 78     int i, j, ll, rr;
 79 
 80     scanf("%d", &case_n);
 81 
 82     while (case_n--) {
 83         scanf("%d", &n);
 84         m = 0;
 85         for (i=1; i<=n; ++i) {
 86             scanf("%d %d", &ls[i], &rs[i]);
 87             buf[m++] = ls[i];
 88             buf[m++] = rs[i];
 89         }
 90         sort(buf, buf+m);
 91         j = 1;
 92         for (i=1; i<m; ++i) {
 93             if (buf[i] != buf[i-1])
 94                 buf[j++] = buf[i];
 95         }
 96         m = j;
 97         for (i=m-1; i>0; --i) {
 98             if (buf[i] != buf[i-1]+1)
 99                 buf[m++] = buf[i-1]+1;
100         }
101         sort(buf, buf+m);
102         //build(0, m, 1);
103         memset(nums, 0, sizeof(nums));
104         memset(set, 0, sizeof(set));
105         for (i=1; i<=n; ++i) {
106             ll = bin(ls[i], m);
107             rr = bin(rs[i], m);
108             update(ll, rr, i, 0, m, 1);
109         }
110         cnt = 0;
111         query(0, m, 1);
112         printf("%d\n", cnt);
113     }
114 
115     return 0;
116 }

 

posted on 2014-06-03 17:17  Bombe  阅读(222)  评论(0)  编辑  收藏  举报

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