[蓝桥杯]真题讲解：合并数列（双指针+贪心）

一、视频讲解

[蓝桥杯]真题讲解：合并数列（双指针+贪心）

二、正解代码

1、C++

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


signed main(){
	int n, m; cin >> n >> m;
	vector<int>a(n), b(m);
	for(int i = 0; i < n; i ++) 
		cin >> a[i];
	for(int j = 0; j < m; j ++)
		cin >> b[j];

	int p1 = 0, s1 = a[0], p2 = 0, s2 = b[0];

	int ans = 0;
	while(p1 < n || p2 < m) {
		if(s1 < s2) {
			p1 ++;
			s1 += a[p1];
			ans ++;
		} else if(s1 > s2) {
			p2 ++;
			s2 += b[p2];
			ans ++;
		}else{
			p1 ++;
			p2 ++;
			if(p1 < n)
				s1 = a[p1];
			if(p2 < m)
				s2 = b[p2];
		}
	}
	cout << ans << endl;
	return 0;
}

2、python3

n, m = map(int, input().split())
a = list(map(int, input().split()))
b = list(map(int, input().split()))
p1, s1, p2, s2 = 0, a[0], 0, b[0]
ans = 0
while p1 < n or p2 < m:
    if s1 < s2:
        p1 += 1
        s1 += a[p1]
        ans += 1
    elif s1 > s2:
        p2 += 1
        s2 += b[p2]
        ans += 1
    else:
        p1 += 1
        p2 += 1
        if p1 < n:
            s1 = a[p1]
        if p2 < m:
            s2 = b[p2]

print(ans)

3、Java

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        List<Integer> a = new ArrayList<>();
        List<Integer> b = new ArrayList<>();
        for(int i = 0; i < n; i ++) {
            int x = sc.nextInt();
            a.add(x);
        }
        for(int i = 0; i < m; i ++) {
            int x = sc.nextInt();
            b.add(x);
        }
        int p1 = 0, s1 = a.get(0), p2 = 0, s2 = b.get(0);
        int ans = 0;
        while(p1 < n || p2 < m) {
            if(s1 < s2){
                p1 ++;
                s1 += a.get(p1);
                ans ++;
            }else if(s1 > s2){
                p2 ++;
                s2 += b.get(p2);
                ans ++;
            }else{
                p1 ++;
                p2 ++;
                if(p1 < n)
                    s1 = a.get(p1);
                if(p2 < m)
                    s2 = b.get(p2);
            }
        }
        System.out.println(ans);
    }
}