미팅 수 최대 더블릿

#include <stdio.h>
#include <algorithm>
 
using namespace std;
 
int dp[1005] = { 0 };
 
int main() {
    int n;
    scanf("%d", &n);
 
    int start, end;
    scanf("%d %d", &start, &end);
    for (int i = 0; i < end; i++)
        dp[i] = 0;
    dp[end] = 1;
    int beforeEnd = end;
 
    for (int i = 2; i <= n; i++) {
        scanf("%d %d", &start, &end);
        for (int j = beforeEnd+1; j < end; j++) {            
            dp[j] = dp[beforeEnd];
        }
        if (dp[end] == 0)
            dp[end] = max(dp[start] + 1, dp[end - 1]);
        else
            dp[end] = max(dp[end], max(dp[start] + 1, dp[end - 1]));
        beforeEnd = end;        
    }
 
    printf("%d", dp[end]);
}