问题描述
小U在公司年会上运气极佳,赢得了一等奖。作为一等奖得主,他有机会在一排红包中做两次切割,将红包分成三部分,要求第一部分和第三部分的红包总金额相等。他可以获得的金额是第一部分红包的总金额。帮小U计算出他能从这些红包中拿到的最大奖金金额。
样例
解决方案
运用双指针方法,从两边向中间寻找
代码
#include <iostream>
#include <vector>
using namespace std;
int solution(std::vector<int> redpacks) {
// Please write your code here
if(redpacks.size()==1||redpacks.size()==2&&redpacks[0]!=redpacks[1]){
return 0;
}
else if(redpacks.size()==2&&redpacks[0]==redpacks[1])
return redpacks[0];
else{
int a=redpacks[0],b=redpacks[redpacks.size()-1];
int sum=0;
int i=1,j=redpacks.size()-2;
while(i<j){
if(a==b&&a>sum){
sum=a;
a+=redpacks[i++];
b+=redpacks[j--];
}
else if(a<b){
a+=redpacks[i++];
}
else {
b+=redpacks[j--];
}
}
if(i==j&&a!=b){
if(a<b){
a+=redpacks[i++];
}
if(a>b){
b+=redpacks[j--];
}
}
if(a==b&&a>sum){
sum=a;
}
return sum;
}
}
int main() {
// You can add more test cases here
std::vector<int> redpacks1 = {1, 3, 4, 6, 7, 14};
std::vector<int> redpacks2 = {10000};
std::vector<int> redpacks3 = {52, 13, 61, 64, 42, 26, 4, 27, 25};
std::vector<int> redpacks4 = {2, 5, 50, 30, 60, 52, 26, 5, 74, 83, 34, 96, 6, 88, 94, 80, 64, 22, 97, 47, 46, 25, 24, 43, 76, 24, 2, 42, 51, 96, 97, 87, 47, 93, 11, 98, 41, 54, 18, 16, 11, 96, 34, 36, 87, 24, 32, 27, 62, 72, 54, 14, 67, 5, 21, 20, 44, 55, 3, 82, 19, 45, 1, 52, 14, 44, 46, 39, 83, 27, 30, 87, 61, 56, 59, 10, 83, 80, 42, 44, 75, 39, 43, 41, 23, 93, 73, 50, 94, 94, 82, 46, 87, 60, 94, 47, 52, 67, 22, 50, 49, 8, 9, 30, 62, 87, 13, 11};
std::cout << (solution(redpacks1) == 14) << std::endl;
std::cout << (solution(redpacks2) == 0) << std::endl;
std::cout << (solution(redpacks3) == 52) << std::endl;
std::cout << (solution(redpacks4) == 2627) << std::endl;
return 0;
}