Topic links: http://acm.hdu.edu.cn/showproblem.php?pid=1003
Subject to the effect:
solving a sequence of maximum field and, starting and ending coordinates have been foremost that the largest sub-segment.
Problem-solving ideas:
the defined state \ (f [i] \) is to \ (a [i] \) at the end of the field and the maximum, there are state transition equation:
\[f[i] = \max(0, f[i-1]) + a[i]\]
At the same time a defined state \ (s [i] \) represented by \ (a [i] \) coordinate of the left end of the element is maximum field, there are:
- 当 \(f[i] \lt 0\) 时，\(s[i] = i\)；
- This \ (f [i] \ ge 0 \) Sometimes, \ (S [I] = S [I-1] \)
Codes are as follows:
#include <bits/stdc++.h>
using namespace std;
const int maxn = 100010;
int T, n, a[maxn], f[maxn], anss, anst, s[maxn], ans;
int main() {
scanf("%d", &T);
for (int cas = 1; cas <= T; cas ++) {
if (cas > 1) puts("");
scanf("%d", &n);
for (int i = 1; i <= n; i ++) scanf("%d", a+i);
ans = f[1] = a[1];
anss = anst = s[1] = 1;
for (int i = 2; i <= n; i ++) {
if (f[i-1] >= 0) {
f[i] = f[i-1] + a[i];
s[i] = s[i-1];
}
else {
f[i] = a[i];
s[i] = i;
}
if (f[i] > ans) {
ans = f[i];
anss = s[i];
anst = i;
}
}
printf("Case %d:\n", cas);
printf("%d %d %d\n", ans, anss, anst);
}
return 0;
}