标签:contain 复杂 span ant bsp 运行 ide name cycle
The task is really simple: given N exits on a highway which forms a simple cycle, you are supposed to tell the shortest distance between any pair of exits.
Each input file contains one test case. For each case, the first line contains an integer N (in [3]), followed by N integer distances D?1?? D?2?? ? D?N??, where D?i?? is the distance between the i-th and the (-st exits, and D?N?? is between the N-th and the 1st exits. All the numbers in a line are separated by a space. The second line gives a positive integer M (≤), with M lines follow, each contains a pair of exit numbers, provided that the exits are numbered from 1 to N. It is guaranteed that the total round trip distance is no more than 1.
For each test case, print your results in M lines, each contains the shortest distance between the corresponding given pair of exits.
5 1 2 4 14 9
3
1 3
2 5
4 1
3 10 7
思路:用数组每个点到第一个点的距离,把时间复杂度控制在O(1),注意:O(n)的时间复杂度会运行超时
#include<bits/stdc++.h> using namespace std; const int maxn=1000010; int nums[maxn]; int dist[maxn]; int main(){ int n,m; cin>>n; int sum=0; dist[0]=0; for(int i=1;i<=n;i++){ cin>>nums[i]; dist[i]=dist[i-1]+nums[i]; sum+=nums[i]; } cin>>m; int a,b; for(int i=0;i<m;i++){ cin>>a>>b; int sum2=0; if(a>b){ swap(a,b); } sum2=dist[b-1]-dist[a-1]; cout<<min(sum-sum2,sum2)<<endl; } return 0; }
标签:contain 复杂 span ant bsp 运行 ide name cycle
原文地址:https://www.cnblogs.com/dreamzj/p/14929005.html