UVa 10035 Primary Arithmetic

解題策略

計算兩數相加總共需要多少次進位，用一般大數加法的技巧，數一下進位次數就行了。

//big number a + b
int carry_count = 0;

for(int i=0;i<MAX_LEN;++i) {

    a[i] = a[i] + b[i];

    if( a[i] > 9 ){
        a[i] = a[i] - 10;
        a[i+1]++;
        carry_count++; //數數進位幾次...
    }
}

注意

輸出時要注意名詞的單複數，總共有三個狀況0、1、其他，別忘了判斷喔。

if(carry_count == 0)
    printf("No carry operation.\n");
else if (carry_count == 1)
    printf("1 carry operation.\n");
else
    printf("%d carry operations.\n", carry_count);

碎碎念

輸出句子最後忘了打句號所以吃了兩次WA....

	/**
	* UVa 10035 Primary Arithmetic
	* Author: chchwy
	* Last Modified: 2011/03/05
	* Blog: http://chchwy.blogspot.com
	*/
	#include<cstdio>
	#include<cstring>
	#include<algorithm>
	using namespace std;
	enum { MAX_LEN = 12 };
	int to_big_number(char* num)
	{
	// reverse
	int len = strlen(num);
	for (int i = 0; i < len / 2; ++i)
	swap(num[i], num[len - i - 1]);
	// sub ascii
	for (int i = 0; i < len; ++i)
	num[i] = num[i] - '0';
	// fill zero
	for (int i = len; i < MAX_LEN; ++i)
	num[i] = 0;
	}
	int count_carry(char* a, char* b)
	{
	to_big_number(a);
	to_big_number(b);
	int carry_counter = 0;
	for (int i = 0; i < MAX_LEN; ++i)
	{
	a[i] = a[i] + b[i];
	if ( a[i] > 9 )
	{
	a[i] = a[i] - 10;
	a[i + 1]++;
	carry_counter++;
	}
	}
	return carry_counter;
	}
	int main()
	{
	#ifndef ONLINE_JUDGE
	freopen("10035.in", "r", stdin);
	#endif
	char a[MAX_LEN], b[MAX_LEN];
	while (scanf("%s %s ", a, b) == 2)
	{
	if (a[0] == '0' && b[0] == '0')
	break;
	int result = count_carry(a, b);
	if ( result == 0)
	printf("No carry operation.\n");
	else if ( result == 1)
	printf("1 carry operation.\n");
	else
	printf("%d carry operations.\n", result);
	}
	return 0;
	}

view raw 10035.cpp hosted with ❤ by GitHub