为什么A1比这题还难

本题：

#include <bits/stdc++.h>
using namespace std;
int lena, lenb, lenc, i;
char n[10005], n1[10005], n2[10005];
int a[10005], b[10005], c[10005];
int main() {
    cin >> n1 >> n2;
    if(strlen(n1) < strlen(n2) || (strlen(n1) == strlen(n2) && strcmp(n1, n2) < 0)) {
        strcpy(n, n1);
        strcpy(n1, n2);
        strcpy(n2, n);
        cout << '-';
    }
    lena = strlen(n1); lenb = strlen(n2);
    for(i = 0; i <= lena - 1; i++) {
        a[lena - i] = int(n1[i] - '0');
    }
    for(i = 0; i <= lenb - 1; i++) {
        b[lenb - i] = int(n2[i] - '0');
    }
    i = 1;
    while(i <= lena || i <= lenb) {
        if(a[i] < b[i]) {
            a[i] += 10;
            a[i + 1]--;
        }
        c[i] = a[i] - b[i];
        i++;
    }
    lenc = i;
    while(c[lenc] == 0 && lenc > 1) lenc--;
    for(i = lenc; i >= 1; i--) {
        cout << c[i];
    }
    return 0;
}

A1:

#pragma G++ optimize(-01)
#pragma G++ optimize(-02)
#pragma G++ optimize(-03)
#pragma G++ optimize("Ofast")
#pragma G++ optimize("inline")
#pragma G++ optimize("-fgcse")
#pragma G++ optimize("-fgcse-lm")
#pragma G++ optimize("-fipa-sra")
#pragma G++ optimize("-ftree-pre")
#pragma G++ optimize("-ftree-vrp")
#pragma G++ optimize("-fpeephole2")
#pragma G++ optimize("-ffast-math")
#pragma G++ optimize("-fsched-spec")
#pragma G++ optimize("unroll-loops")
#pragma G++ optimize("-falign-jumps")
#pragma G++ optimize("-falign-loops")
#pragma G++ optimize("-falign-labels")
#pragma G++ optimize("-fdevirtualize")
#pragma G++ optimize("-fcaller-saves")
#pragma G++ optimize("-fcrossjumping")
#pragma G++ optimize("-fthread-jumps")
#pragma G++ optimize("-funroll-loops")
#pragma G++ optimize("-fwhole-program")
#pragma G++ optimize("-freorder-blocks")
#pragma G++ optimize("-fschedule-insns")
#pragma G++ optimize("inline-functions")
#pragma G++ optimize("-ftree-tail-merge")
#pragma G++ optimize("-fschedule-insns2")
#pragma G++ optimize("-fstrict-aliasing")
#pragma G++ optimize("-fstrict-overflow")
#pragma G++ optimize("-falign-functions")
#pragma G++ optimize("-fcse-skip-blocks")
#pragma G++ optimize("-fcse-follow-jumps")
#pragma G++ optimize("-fsched-interblock")
#pragma G++ optimize("-fpartial-inlining")
#pragma G++ optimize("no-stack-protector")
#pragma G++ optimize("-freorder-functions")
#pragma G++ optimize("-findirect-inlining")
#pragma G++ optimize("-frerun-cse-after-loop")
#pragma G++ optimize("inline-small-functions")
#pragma G++ optimize("-finline-small-functions")
#pragma G++ optimize("-ftree-switch-conversion")
#pragma G++ optimize("-foptimize-sibling-calls")
#pragma G++ optimize("-fexpensive-optimizations")
#pragma G++ optimize("-funsafe-loop-optimizations")
#pragma G++ optimize("inline-functions-called-once")
#pragma G++ optimize("-fdelete-null-pointer-checks") 
#include <bits/stdc++.h>
using namespace std;
int n, x;
struct node {
	int data;
	node * next;
};
int main() {
	const int MAX = 2;
    n = MAX;
	node * head, * r, * p, * q;
	head = new node;
	head -> next = NULL;
	r = head;
	for(int i = 1; i <= n; i++) {
		cin >> x;
		p = new node;
		p -> data = x;
		p -> next = NULL;
		r -> next = p;
		r = p;
	}
	p = head;
	while(p -> next != NULL) {
		printf("%d", p -> next -> data + p -> next -> next -> data);
		return 0; 
		p = p -> next;
	}
	return 0;
}