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CF846C.Four Segments
Four Segments
CF846C · Four Segments
- 难度:1800
- 标签:brute force、data structures、dp
- 链接:https://codeforces.com/problemset/problem/846/C
- 时间限制:1 second 内存限制:256 megabytes
- 出现位置:Day17-树形DP-区间DP-计数DP
英文原题面
Statement
You are given an array of n integer numbers. Let sum(l, r) be the sum of all numbers on positions from l to r non-inclusive (l-th element is counted, r-th element is not counted). For indices l and r holds 0 ≤ l ≤ r ≤ n. Indices in array are numbered from 0. For example, if a = [ - 5, 3, 9, 4], then sum(0, 1) = - 5, sum(0, 2) = - 2, sum(1, 4) = 16 and sum(i, i) = 0 for each i from 0 to 4. Choose the indices of three delimiters delim0, delim1, delim2 (0 ≤ delim0 ≤ delim1 ≤ delim2 ≤ n) and divide the array in such a way that the value of res = sum(0, delim0) - sum(delim0, delim1) + sum(delim1, delim2) - sum(delim2, n) is maximal. Note that some of the expressions sum(l, r) can correspond to empty segments (if l = r for some segment).
Input
The first line contains one integer number n (1 ≤ n ≤ 5000). The second line contains n numbers a0, a1, ..., an - 1 ( - 109 ≤ ai ≤ 109).
Output
Choose three indices so that the value of res is maximal. If there are multiple answers, print any of them.
样例
样例 1
输入:
3
-1 2 3
输出:
0 1 3
样例 2
输入:
4
0 0 -1 0
输出:
0 0 0
样例 3
输入:
1
10000
输出:
1 1 1
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