[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 += 1s1 += a[p1]ans += 1elif s1 > s2:p2 += 1s2 += b[p2]ans += 1else:p1 += 1p2 += 1if 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);}
}