HDU6183(线段树)

xiaoxiao2021-02-28  75

Color it

Time Limit: 20000/10000 MS (Java/Others)    Memory Limit: 132768/132768 K (Java/Others) Total Submission(s): 302    Accepted Submission(s): 62 Problem Description Do you like painting? Little D doesn't like painting, especially messy color paintings. Now Little B is painting. To prevent him from drawing messy painting, Little D asks you to write a program to maintain following operations. The specific format of these operations is as follows. 0  : clear all the points. 1   x   y   c  : add a point which color is  c  at point  (x,y) . 2   x   y1   y2  : count how many different colors in the square  (1,y1)  and  (x,y2) . That is to say, if there is a point  (a,b)  colored  c , that  1ax  and  y1by2 , then the color  c  should be counted. 3  : exit.   Input The input contains many lines.  Each line contains a operation. It may be '0', '1 x y c' (  1x,y106,0c50  ), '2 x y1 y2' ( 1x,y1,y2106  ) or '3'.  x,y,c,y1,y2  are all integers. Assume the last operation is 3 and it appears only once. There are at most  150000  continuous operations of operation 1 and operation 2.  There are at most  10  operation 0.    Output For each operation 2, output an integer means the answer .   Sample Input 0 1 1000000 1000000 50 1 1000000 999999 0 1 1000000 999999 0 1 1000000 1000000 49 2 1000000 1000000 1000000 2 1000000 1 1000000 0 1 1 1 1 2 1 1 2 1 1 2 2 2 1 1 2 1 2 2 2 2 1 1 2 1 2 1 3 2 2 1 2 2 10 1 2 2 10 2 2 0 1 1 1 1 2 1 1 1 1 1 2 1 2 1 1 2 1 2 2 1 2 1 1 2 1 2 1 1 2 2 1 2 2 10 1 2 2 10 2 2 3   Sample Output 2 3 1 2 2 3 3 1 1 1 1 1 1 1   Source 2017ACM/ICPC广西邀请赛-重现赛(感谢广西大学) 解题思路:刚开始觉得这题很麻烦,因为可能会有点覆盖的情况,就是一个点先被一种颜色覆盖,然后被另外一种颜色覆盖,那么之前的颜色就没有了,但是,这题不会出现这种情况,就算被覆盖了,也算有两种颜色,从样例就可以看出,那么问题就变得很简单了,我们用50棵线段树搞一搞就行,我们按y坐标建树,维护x的最小值(为什么这样做,因为每次询问的矩形的左下点的横坐标是1,所以这样做可以化双边界约束为单边界,我们维护最小值就行),这里50棵线段树可能会超内存,所以要边更新,边建树,这样动态建树的话空间复杂度为O(n * logn),因为每次更新,最多消耗logn个顶点。 #include <bits/stdc++.h> using namespace std; const int maxn = 1000000 + 10; int inf = 0x3f3f3f3f; struct node { int l, r; int lson, rson; int sum; int Min; node() { sum = 0; Min = inf; lson = rson = 0; } }Node[maxn<<2]; int tot; int root[55]; int judge; void update(int &rt, int l, int r, int value, int Mi) { if(!rt) rt = ++tot; Node[rt].l = l; Node[rt].r = r; Node[rt].sum++; Node[rt].Min = min(Node[rt].Min, Mi); if(l == r) return; int mid = (l + r)>>1; if(value <= mid) update(Node[rt].lson, l, mid, value, Mi); else update(Node[rt].rson, mid + 1, r, value, Mi); } void query(int rt, int l, int r, int up) { if(!rt || judge) return; if(Node[rt].l == l && Node[rt].r == r) { if(Node[rt].Min <= up && Node[rt].sum > 0) { judge = 1; return; } return; } int mid = (Node[rt].l + Node[rt].r)>>1; if(r <= mid) query(Node[rt].lson, l, r, up); else if(l >= mid + 1) query(Node[rt].rson, l, r, up); else { query(Node[rt].lson, l, mid, up); query(Node[rt].rson, mid + 1, r, up); } } void init() { tot = 0; memset(root, 0, sizeof(root)); for(int i = 0; i < (maxn<<2); i++) { Node[i].lson = Node[i].rson = Node[i].sum = 0; Node[i].Min = inf; } } int main() { int op; init(); while(~scanf("%d", &op) && op != 3) { if(op == 0) init(); else if(op == 1) { int x, y, c; scanf("%d%d%d", &x, &y, &c); update(root[c], 1 , 1000000, y, x); } else if(op == 2) { int x, y1, y2; scanf("%d%d%d", &x, &y1, &y2); int ans = 0; for(int i = 0; i <= 50; i++) { judge = 0; query(root[i], y1, y2, x); if(judge) { ans++; } } printf("%d\n", ans); } } return 0; }  
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