【C++】0314算法阿里笔试题

一、题目

二、 自己的dfs的题解

我并没有参加这个笔试，这种方法应该A不了所有用例，有什么错误的地方恳请指导指导(*￣︶￣) respect

#include <bits/stdc++.h>
using namespace std;

int res3=INT_MAX;
int transfet(vector<string> &tmp) {
    int sum=0;
    for (auto &t: tmp) {
        sum += stoi(t);
    }
    return sum;
}
void dfs(string str, vector<string> &tmp, int start, int nums, int k) {
    if (start==str.size()) { //str.size()==0
        if (!(transfet(tmp)%k)) {
            res3 = min(res3, nums-1);
            return;
        }
        else return;
    }
    for (int i=start; i<str.size(); i++) {
        int end = i;
        tmp.emplace_back(str.substr(start ,end-start+1));
        bfs(str, tmp, end+1, nums+1, k);
        tmp.pop_back();
    }
}
int leastNum(string str, int k) {  
    vector<string> tmp;
    dfs(str, tmp, 0, 0, k);
    return res3;
}
int main(int argc, char* argv[])
{
	vector<string> a = {"1","34","567"};
	cout<<transfet(a)<<endl;
	string s = "1231";
	cout<<"最小的次数："<<leastNum(s, 5)<<endl; // 结果为2
}

在牛客上看到的大佬的DP做法，如下：
其余的题目信息见：阿里笔试(0314算法岗)

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

vector<int> gao(ll n, int k) {
	string s = to_string(n);
	vector<vector<int>> dp(s.size()+1, vector<int>(k, 0x3f3f3f3f));
	dp[0][0] = 0;
	for (int i = 0; i < s.size(); i++) {
		int cur = 0;
		for (int j = i; j < s.size(); j++) {
			cur = (cur * 10 + s[j]-'0')%k;
	    	for (int x = 0; x < k; x++) {
	      		dp[j+1][(cur+x)%k] = min(dp[j+1][(cur+x)%k] , dp[i][x]+(i!=0));
	    	}
	  	}
	}
	return dp.back();
}

int main() {
	int n, k; cin >> n >> k;
	vector<ll> A(n); for (auto &x: A) cin >> x;
	vector<int> cur(k, 0x3f3f3f3f);
	cur[0] = 0;
	for (auto &t: A) {
	 	vector<int> nxt(k, 0x3f3f3f3f);
		vector<int> tmp = gao(t, k);
	  	for (int i = 0; i < k; i++) {
	    	for (int j = 0; j < k; j++) nxt[(i+j)%k] = min(nxt[(i+j)%k], cur[i]+tmp[j]); 
	 	}
		cur = nxt;
	}
	cout << cur[0] << endl;
}