POJ-2528-Mayor's posters

POJ-2528-Mayor's posters

Http://poj.org/problem? Id = 2528

The discretization of the Line Segment tree is equivalent to first ing and then building

Test data for the question

1 4

2 6

8 10

3 4

7 10

Extracts and sorts the endpoints, and removes the same coordinates, that is, 1, 2, 3, 4, 6, 7, 8, 10.

1, 2, 3, 4, 6, 7, 8, 10 can be discretization

1, 2, 3, 4, 5, 6, 7, 8

The range given by the question can be expressed

1 4

2 5

7 8

3 4

6 8

This will reduce the building space.

# Include <iostream> # include <cstdio> # include <cstring> # include <cstdlib> # include <algorithm> using namespace std; # define Max 10010 struct cam1 {int l, r;} post [Max]; int x [Max * 2]; // coordinate int h [10000005]; struct cam2 {int l, r; int flag; // mark whether it is overwritten} list [Max * 8]; int cmp (const void * a, const void * B) {return * (int *) a-* (int *) B;} void build (int k, int l, int r) {list [k]. l = l; list [k]. r = r; list [k]. flag = 0; if (l = r) return; int mid = (l + r)/2; build (k <1, l, mid ); build (k <1 | 1, mid + 1, r);} int query (int k, int l, int r) {if (list [k]. flag) return 0; if (list [k]. l = l & list [k]. r = r) {list [k]. flag = 1; return 1;} int result, mid; mid = (list [k]. l + list [k]. r)/2; if (r <= mid) result = query (k <1, l, r); else if (l> mid) result = query (k <1 | 1, l, r); elseresult = query (k <1, l, mid) | query (k <1 | 1, mid + 1, r); if (list [k <1]. flag & list [k <1 | 1]. flag) // report the child node to the parent node list [k]. flag = 1; return result;} int main () {int t, cnt; int I, j, k, n, ans; scanf ("% d", & t ); while (t --) {scanf ("% d", & n); cnt = 0; for (I = 0; I <n; I ++) {scanf ("% d", & post [I]. l, & post [I]. r); x [cnt ++] = post [I]. l; x [cnt ++] = post [I]. r;} sort (x, x + cnt); // sort cnt = unique (x, x + cnt)-x from small to large; // remove the same coordinates for (I = 0; I <cnt; I ++) h [x [I] = I; build (, cnt-1 ); ans = 0; for (I = n-1; I> = 0; I --) if (query (1, h [post [I]. l], h [post [I]. r]) ans ++; printf ("% d \ n", ans) ;}return 0 ;}