腾讯笔试 记录一下
虽然自己面试已经挂了，但是还是做了一下笔试。前面4题没啥难度的，最后一题是个区间DP。
#include <iostream>
#include <vector>
using namespace std;
int n;
vector<int> num;
void slove() {
int n = num.size();
vector<vector<int>> left (n, vector<int>(n, 0)); //向左归并
vector<vector<int>> right(n, vector<int>(n, 0)); //向右归并
for (int len = 2; len <= n; len++) {
for (int i = 0; i + len - 1 < n; i++) {
int j = i + len - 1;
int tmp_left = num[i], tmp_right = num[j];
left[i][j] = min(left[i + 1][j] + abs(tmp_left - num[i + 1]), right[i + 1][j] + abs(tmp_left - num[j]));
right[i][j] = min(right[i][j-1] + abs(tmp_right - num[j-1]), left[i][j-1] + abs(tmp_right - num[i]));
}
}
cout << min(left[0][n - 1], right[0][n - 1]) << endl;
}
int main() {
int t;
cin >> n;
while (n--) {
cin >> t;
num.push_back(t);
}
slove();
return 0;
} 第四题：
//k=str.size()-n; k代表需要删除字母的个数
//解题思路 贪心
string slove(string str, int k) {
if (str.size() <= k) return "";
string res;
int count = 0;
for (int i = 0; i < str.size(); i++) {
if (res.size() == 0) res += str[i];
else if (res.back() < str[i] && count < k) {
while (res.back() < str[i] && count < k) {
count++; res.pop_back();
}
res += str[i];
}
else res += str[i];
}
while (count < k) res.pop_back()，count++;
return res;
} 
