2017 CCPC 秦皇岛 M - Safest Buildings 【几何&概率】
2017-12-17 00:57
543 查看
PUBG is a multiplayer online battle royale video game. In the game, up to one hundred players parachute onto an island and scavenge for weapons and equipment to kill others while avoiding getting killed themselves. BaoBao is a big fan of the game, but this time he is having some trouble selecting the safest building.
There are buildings scattering on the island in the game, and we consider these buildings as points on a two-dimensional plane. At the beginning of each round, a circular safe area whose center is located at (0, 0) with radius will be spawned on the island. After some time, the safe area will shrink down towards a random circle with radius (). The whole new safe area is entirely contained in the original safe area (may be tangent to the original safe area), and the center of the new safe area is uniformly chosen within the original safe area.
The buildings covered by the new safe area is called the safe buildings. Given the radius of the safe areas and the positions of the buildings, BaoBao wants to find all the buildings with the largest probability to become safe buildings.
Input
There are multiple test cases. The first line of input contains an integer , indicating the number of test cases. For each test case:
The first line contains three integers (), and (), indicating the number of buildings and the radius of two safe circles.
The following lines each contains 2 integers and (), indicating the coordinate of the buildings. Here we assume that the center of the original safe circle is located at , and all the buildings are inside the original circle.
It’s guaranteed that the sum of over all test cases will not exceed 5000.
Output
For each test case output two lines.
The first line contains an integer , indicating the number of buildings with the highest probability to become safe buildings.
The second line contains integers separated by a space in ascending order, indicating the indices of safest buildings.
Please, DO NOT output extra spaces at the end of each line.
Sample Input
2
3 10 5
3 4
3 5
3 6
3 10 4
-7 -6
4 5
5 4
Sample Output
1
1
2
2 3
题意:绝地求生游戏题。给出许多建筑,和一个原始安全圈。然后再原始安全圈内部更新一个新的安全圈。求哪个或者哪些个建筑最容易成为安全的地方。题目保证所有建筑都在原始安全圈之内!
分析:如果2∗r>=R ,存在完全安全区,如果2∗r<R ,存在存活概率相同的安全区。此外,生存概率递减。
There are buildings scattering on the island in the game, and we consider these buildings as points on a two-dimensional plane. At the beginning of each round, a circular safe area whose center is located at (0, 0) with radius will be spawned on the island. After some time, the safe area will shrink down towards a random circle with radius (). The whole new safe area is entirely contained in the original safe area (may be tangent to the original safe area), and the center of the new safe area is uniformly chosen within the original safe area.
The buildings covered by the new safe area is called the safe buildings. Given the radius of the safe areas and the positions of the buildings, BaoBao wants to find all the buildings with the largest probability to become safe buildings.
Input
There are multiple test cases. The first line of input contains an integer , indicating the number of test cases. For each test case:
The first line contains three integers (), and (), indicating the number of buildings and the radius of two safe circles.
The following lines each contains 2 integers and (), indicating the coordinate of the buildings. Here we assume that the center of the original safe circle is located at , and all the buildings are inside the original circle.
It’s guaranteed that the sum of over all test cases will not exceed 5000.
Output
For each test case output two lines.
The first line contains an integer , indicating the number of buildings with the highest probability to become safe buildings.
The second line contains integers separated by a space in ascending order, indicating the indices of safest buildings.
Please, DO NOT output extra spaces at the end of each line.
Sample Input
2
3 10 5
3 4
3 5
3 6
3 10 4
-7 -6
4 5
5 4
Sample Output
1
1
2
2 3
题意:绝地求生游戏题。给出许多建筑,和一个原始安全圈。然后再原始安全圈内部更新一个新的安全圈。求哪个或者哪些个建筑最容易成为安全的地方。题目保证所有建筑都在原始安全圈之内!
分析:如果2∗r>=R ,存在完全安全区,如果2∗r<R ,存在存活概率相同的安全区。此外,生存概率递减。
#include <iostream> #include <string.h> #include <stdio.h> #include <algorithm> using namespace std; const int maxn = 100+10; struct node { int s; int flag; } a[maxn]; int dis(int x,int y) { return x*x+y*y; } bool cmd(node a,node b) { if(a.s!=b.s) return a.s<b.s; return a.flag<b.flag; } int main() { int T; scanf("%d",&T); while(T--) { int n,R,r; scanf("%d %d %d",&n,&R,&r); for(int i=1; i<=n; i++) { int x,y; scanf("%d %d",&x,&y); a[i].flag=i; a[i].s=dis(x,y); } sort(a+1,a+1+n,cmd); int cnt=0; int ans[maxn]; if(R-2*r<=0) { int d=2*r-R; for(int i=1; i<=n; i++) { if(a[i].s<=d*d) { cnt++; ans[cnt]=a[i].flag; } } } if(cnt!=0) { printf("%d\n",cnt); sort(ans+1,ans+1+cnt); for(int i=1; i<=cnt; i++) { printf("%d%c",ans[i],i==cnt?'\n':' '); } continue; } for(int i=1;i<=n;i++){ if(a[i].s<=(R-2*r)*(R-2*r)){ ans[++cnt]=a[i].flag; }else{ break; } } if(cnt!=0){ printf("%d\n",cnt); sort(ans+1,ans+1+cnt); for(int i=1; i<=cnt; i++) { printf("%d%c",ans[i],i==cnt?'\n':' '); } continue; } int now=a[1].s; cnt++; for(int i=2; i<=n; i++) { if(a[i].s==now) { cnt++; } else { break; } } printf("%d\n",cnt); for(int i=1; i<=cnt; i++) { ans[i]=a[i].flag; } sort(ans+1,ans+1+cnt); for(int i=1; i<=cnt; i++) { printf("%d%c",ans[i],i==cnt?'\n':' '); } } return 0; }
相关文章推荐
- 2017 CCPC 秦皇岛 & ZOJ 3993 - Safest Buildings (概率+规律)
- 2017 CCPC 秦皇岛 & ZOJ 3981 - Balloon Robot 规律
- 2017 CCPC 秦皇岛 & ZOJ 3983 - Crusaders Quest
- 2017 ccpc 秦皇岛 M(几何)
- 2017 CCPC 秦皇岛 & ZOJ 3985 - String of CCPC (子串)
- 2017 CCPC 秦皇岛 & ZOJ 3987 - Numbers (贪心+大数)
- 2017 ccpc 秦皇岛C Crusaders Quest
- 2017 CCPC 秦皇岛
- 2017 CCPC 秦皇岛 A:Balloon Robot
- 2017 CCPC秦皇岛 B
- 2017 CCPC秦皇岛 H题 Prime set
- 2017 CCPC 秦皇岛 L - One-Dimensional Maze 【water】
- 2017 ACM-CCPC 秦皇岛站 总结
- 2017 ccpc 秦皇岛E String of CCPC
- hdu6237-2017哈尔滨CCPC-质因子&贪心&暴力-A Simple Stone Game
- 2017 CCPC 秦皇岛
- ZOJ 3985 && 2017CCPC秦皇岛 E:String of CCPC
- 2017 CCPC秦皇岛 L题 One Dimensions Dave
- 2017 ccpc秦皇岛L One-Dimensional Maze
- 2017 CCPC-WFinal&&HDOJ 6030 Happy Necklace(矩阵快速幂)