《Cracking the Coding Interview》——第17章：普通题——题目8

 1 // 17.8 Find the consecutive subarray with maximum sum in an array.
 2 // O(n) online algorithm.
 3 #include <cstdio>
 4 #include <vector>
 5 using namespace std;
 6 
 7 int maximumSum(vector<int> &v)
 8 {
 9     int n = (int)v.size();
10     
11     if (n == 0) {
12         return 0;
13     }
14     
15     int val = v[0];
16     int i;
17     
18     for (i = 1; i < n; ++i) {
19         val = val > v[i] ? val : v[i];
20     }
21     
22     if (val <= 0) {
23         return val;
24     }
25     
26     int res;
27     res = val = 0;
28     for (i = 0; i < n; ++i) {
29         val += v[i];
30         if (val > res) {
31             res = val;
32         }
33         if (val < 0) {
34             val = 0;
35         }
36     }
37     
38     return res;
39 }
40 
41 int main()
42 {
43     vector<int> v;
44     int n, i;
45     
46     while (scanf("%d", &n) == 1 && n > 0) {
47         v.resize(n);
48         for (i = 0; i < n; ++i) {
49             scanf("%d", &v[i]);
50         }
51         printf("%d\n", maximumSum(v));
52         v.clear();
53     }
54     
55     return 0;
56 }