LeetCode上也有这道题，直接扫一遍就行了，连数组都不用开，感觉像是蕴含了某种动归的思想在里面，要不怎么是个动归题呢
代码：
1 #include <cmath> 2 #include <cstdio> 3 #include <vector> 4 #include <iostream> 5 #include <algorithm> 6 using namespace std; 7 8 int main() { 9 /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 10 int n; 11 int curr_score, prev_score, curr_cnt; 12 int dir, len; 13 int res = 0; 14 15 prev_score = -1; 16 curr_cnt = 0; 17 dir = 1; 18 scanf("%d", &n); 19 for (int i = 0; i < n; i++) { 20 scanf("%d", &curr_score); 21 if (curr_score > prev_score) { 22 if (dir < 0) { 23 res += (1 - curr_cnt) * (len + (int) (curr_cnt <= 0)); 24 curr_cnt = 1; 25 } 26 curr_cnt += 1; 27 res += curr_cnt; 28 dir = 1; 29 } else if (curr_score < prev_score) { 30 if (dir >= 0) 31 len = 0; 32 curr_cnt -= 1; 33 res += curr_cnt; 34 dir = -1; 35 len += 1; 36 } else { 37 if (dir < 0) 38 res += (1 - curr_cnt) * (len + (int) (curr_cnt <= 0)); 39 curr_cnt = 1; 40 res += curr_cnt; 41 dir = 0; 42 } 43 prev_score = curr_score; 44 } 45 if (dir < 0) 46 res += (1 - curr_cnt) * (len + (int) (curr_cnt <= 0)); 47 48 cout << res << endl; 49 50 return 0; 51 }