2018 Multi-University Training Contest 1

Posted 2021-01-07 qywhy

1001:题面

题意:给定一个数n，找出三个正整数x、y和z，满足：n=x+y+z,x|n,y|n,z|n。然后求xyz的最大值。

题解:1=1/2+3/1+1/6=1/3+1/3+1/3=1/2+1/4+1/4 所以就三种

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef long long LL;
 4 int main() {
 5     int T;
 6     scanf("%d", &T);
 7     while(T--) {
 8         LL n;
 9         scanf("%lld", &n);
10         if(n % 3 == 0) {
11             LL ans = n / 3;
12             ans = ans * ans * ans;
13             printf("%lld
", ans);
14         }
15         else if(n % 4 == 0) {
16             LL a = n / 4;
17             LL b = n / 2;
18             LL ans = a * a * b;
19             printf("%lld
", ans);
20         }
21         else puts("-1");
22     }
23     return 0;
24 }

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1003:题面

题意:给出3*N个点,让你输出N个三角形使得他们互不相交, 题目输出保证不会有三点共线。

题解:因为不会有三点共线的情况,所以直接按x排序,直接输出即可

 1 #include <bits/stdc++.h>
 2 #define N 5005
 3 using namespace std;
 4 struct Node {
 5     int x,y,index;
 6 } node[N];
 7 bool cmp(Node a, Node b) 
 8 {
 9     if(a.x == b.x) return a.y < b.y;
10     return a.x < b.x;
11 }
12 int main() 
13 {
14     int T;
15     scanf("%d", &T);
16     while(T--) 
17     {
18         int n;
19         scanf("%d", &n);
20         for(int i = 1; i <= 3 * n; ++i) 
21         {
22             scanf("%d%d", &node[i].x, &node[i].y);
23             node[i].index = i;
24         }
25         sort(node + 1, node + 1 + 3 * n, cmp);
26         for(int i = 1; i <= 3 * n; i += 3) 
27             printf("%d %d %d
", node[i].index, node[i + 1].index, node[i + 2].index);
28     }
29     return 0;
30 }

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