CodeForces 831A:Unimodal Array(模拟)
2017-08-01 20:48
691 查看
Unimodal Array
Time limit:1000 ms Memory limit:262144 kB OS:LinuxProblem Description
Array of integers is unimodal, if:it is strictly increasing in the beginning;
after that it is constant;
after that it is strictly decreasing.
The first block (increasing) and the last block (decreasing) may be absent. It is allowed that both of this blocks are absent.
For example, the following three arrays are unimodal: [5, 7, 11, 11, 2, 1], [4, 4, 2], [7], but the following three are not unimodal: [5, 5, 6, 6, 1], [1, 2, 1, 2], [4, 5, 5, 6].
Write a program that checks if an array is unimodal.
Input
The first line contains integer n (1 ≤ n ≤ 100) — the number of elements in the array.The second line contains n integers a1, a2, …, an (1 ≤ ai ≤ 1 000) — the elements of the array.
Output
Print “YES” if the given array is unimodal. Otherwise, print “NO”.You can output each letter in any case (upper or lower).
Example
Note
In the first example the array is unimodal, because it is strictly increasing in the beginning (from position 1 to position 2, inclusively), that it is constant (from position 2 to position 4, inclusively) and then it is strictly decreasing (from position 4 to position 6, inclusively).题意:
给出一个序列,判断其是否是按照:严格递增,相等,严格递减的格式,其中第一段和第三段可以没有解题思路:
找到最大的那个数字的下标,然后往左判断是否严格递减,然后走到最后一个相同的元素,往右判断是否严格递减Code:
#include <iostream> #include <algorithm> #include <cstdio> #include <cstring> #define mem(a,b) memset(a,b,sizeof(a)) using namespace std; const int maxn=100+5; int a[maxn]; int main() { int n; while(scanf("%d",&n)!=EOF) { int m=0; for(int i=0; i<n; i++) { scanf("%d",a+i); if(a[m]<a[i]) m=i; } int flag=1; for(int i=m-1; i>=0; i--) { if(a[i]>=a[i+1]) { flag=0; break; } } while(a[m]==a[m+1]&&m<n-1) m++; for(int i=m+1; i<n; i++) { if(a[i]>=a[i-1]) { flag=0; break; } } if(flag) printf("YES\n"); else printf("No\n"); } return 0; }
相关文章推荐
- Codeforces - 831A. Unimodal Array - 模拟
- CodeForces 831A Unimodal Array
- CodeForces 831A-Unimodal Array
- CodeForces - 831A Unimodal Array
- (CodeForces - 831A)Unimodal Array
- codeforces 831A Unimodal Array
- codeforces 442C C. Artem and Array(有深度的模拟)
- E - Unimodal Array CodeForces - 831A
- E - Unimodal Array CodeForces - 831A
- 2018.2.4【 CodeForces - 831A 】解题报告(模拟)
- CodeForces 360A - Levko and Array Recovery (模拟)
- Codeforces 831 A Unimodal Array
- CodeFroces 831A. Unimodal Array(构造题)
- codeforces 251 div2 C. Devu and Partitioning of the Array 模拟
- 1/21集训二 模拟+贪心 E.(模拟 判断一组序列是否满足先增再平后减)Unimodal Array
- CodeForces - 831A Unimodal Array 模拟
- CodeForces - 831A Unimodal Array 模拟
- CodeForces 118C 【模拟】
- Codeforces626B - Cards【模拟】
- Codeforces 906A Shockers (模拟)