8.25 bilibili 算法笔试
不太清楚哪些边界条件没有判断，比如它题目中给出 fee > 0 ，我还需要在程序里判断一下嘛？
（好像测试的时候，判断 fee <= 0，过的案例更少了，不知道是什么问题
求大佬们指教一下！！感谢感谢！！！
1. 股票 0.83
#include<bits/stdc++.h>
using namespace std;
int main(){
string str;
cin >> str;
if (str.size() <= 2) return 0;
vector<int> price;
for (int i = 1; i < str.size() - 1; i += 2){
if (str[i] <= '9' && str[i] >= '0'){
int tmp = str[i] - '0';
price.push_back(tmp);
}
}
int fee;
cin >> fee;
int n = price.size();
vector<vector<int>> dp(n, vector<int>(2, 0));
dp[0][0] -= price[0];
for (int i = 1; i < n; ++i){
dp[i][0] = max(dp[i - 1][0], dp[i - 1][1] - price[i]);
dp[i][1] = max(dp[i - 1][1], dp[i - 1][0] + price[i] - fee);
}
cout << max(dp[n - 1][0], dp[n - 1][1]);
return 0;
} #include<bits/stdc++.h>
using namespace std;
int main(){
int A[12];
for (int i = 1; i <= 10; i++) cin >> A[i];
A[0] = A[10];
A[11] = A[1];
int temp[12];
int m;
cin >> m;
while (m--){
for (int i = 1; i <= 10; i++){
temp[i] = A[i - 1] ^ A[i + 1];
}
for (int j = 1; j <= 10; j++){
A[j] = temp[j];
}
A[0] = temp[10];
A[11] = temp[1];
}
for (int i = 1; i <= 10; i++) cout << A[i] << ' ';
return 0;
} 3. score 0.5
#include<bits/stdc++.h>
using namespace std;
#define ll long long
int A[300010];
ll sumA[300010]; // 前 i 个数的和
int n, k;
ll res = LLONG_MIN;
void backtracking(int K, int Sum, int startIndex){
if (K == k){
if (startIndex < n){
Sum += K * (sumA[n] - sumA[startIndex] + A[startIndex]);
res = res > Sum ? res : Sum;
}
return;
}
for (int i = startIndex; i <= n - 1 -(k - K); i++){
if (i == 0) continue;
Sum += K * (sumA[i] - sumA[startIndex] + A[startIndex]);
K++;
backtracking(K, Sum, i + 1);
K--;
Sum -= K * (sumA[i] - sumA[startIndex] + A[startIndex]);
}
}
int main(){
cin >> n >> k;
for (int i = 1; i <= n; ++i) cin >> A[i];
for (int i = 1; i <= n; ++i) sumA[i] += sumA[i - 1] + A[i]; // sumA[0] = 0;
backtracking(1, 0, 0);
cout << res;
return 0;
} 
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