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  1. #include <iostream>
  2. #include <bits/stdc++.h>
  3. using namespace std;
  4.  
  5.  
  6.  
  7.  
  8. void reverse(char *str){
  9.  
  10. 	int  i = 0;
  11. 	int  j = strlen(str)-1;
  12.  
  13. 	while(i < j){
  14.  
  15. 		char c = str[i];
  16. 		str[i] = str[j];
  17. 		str[j] = c;
  18. 		i++;
  19. 		j--;
  20.  
  21. 	}
  22. 	return ;
  23.  
  24.  
  25. }
  26.  
  27.  
  28. void swap2(char *str1, char *str2)
  29. {
  30.   char *temp = (char *)malloc((strlen(str1) + 1) * sizeof(char));
  31.   strcpy(temp, str1);
  32.   strcpy(str1, str2);
  33.   strcpy(str2, temp);
  34.   free(temp);
  35. }  
  36.  
  37. void shiftRight(char *arr,int n)
  38. {
  39.  
  40. 	char tmp[30001];
  41. 	int i;
  42.  
  43.  
  44. 	// cout << arr <<endl;
  45. 	for( i =0; i < n ;i++)
  46. 		tmp[i] ='0';
  47.  
  48. 		int index =0;
  49. 		int k;
  50.  
  51.  
  52. 		// for( k =i ; k < i+strlen(arr)-1; k++){
  53. 		// 	tmp[k] = arr[index];
  54. 		// 	index++;
  55. 		// }
  56.  
  57. 		 k = i;
  58.  
  59.  
  60. 		 //cout << k << "before " <<i+strlen(arr)-1<<endl;
  61. 		while(k <= i+strlen(arr)-1){
  62.  
  63. 			 tmp[k] = arr[index];
  64. 			index++;
  65. 			k++;
  66. 		}
  67.  
  68.  
  69.  
  70. 		tmp[k] = '\0';
  71.  
  72. 		// cout <<"222"<< tmp <<endl;
  73.  
  74. 		int j;
  75. 		// cout << endl;
  76.  
  77.  
  78.  
  79. 	 strcpy(arr, tmp);
  80. 	 //cout << arr <<endl;
  81.  
  82.  
  83. }
  84.  
  85.  
  86. void add(char *num1, char *num2){
  87.  
  88.  
  89. 	 int num;
  90. 	 int carry = 0;
  91. 	 int dig;
  92.  
  93.  
  94.  
  95. 	 if(strlen(num2) > strlen(num1))
  96. 		swap2(num1, num2);
  97.  
  98. 		int i ;
  99. 		for( i = 0; i < strlen(num2); i++)
  100. 		    {
  101.  
  102.  
  103. 		    	num = num1[i]-'0' + num2[i]-'0' +carry;
  104. 		    	dig = num %10;
  105. 		    	carry = num/10;
  106.  
  107. 		    	num1[i] = dig +'0';
  108. 		    }
  109.  
  110.  
  111. 		   while(i < strlen(num1)){
  112.  
  113. 		    	num = num1[i]-'0'  +carry;
  114. 		    	dig = num %10;
  115. 		    	carry = num/10;
  116.  
  117. 		    	num1[i] = dig+'0';
  118. 		    	i++;
  119. 		   }
  120.  
  121. 		   while(carry > 0){
  122.  
  123.  
  124. 		    	dig = carry %10;
  125. 		    	carry = carry/10;
  126.  
  127. 		    	num1[i] = dig+'0';
  128. 		    	i++;
  129.  
  130. 		   }
  131.  
  132. 		   num1[i] = '\0';
  133.  
  134.  
  135.  
  136.  
  137.  
  138. }
  139.  
  140. void mul(char *num1, char *num2){
  141.  
  142. 	  char prev[30001];
  143. 	  char curr[30001];
  144.  
  145.  
  146. 	  for(int i = 0 ; i < 30001; i++)
  147. 		prev[i] = '0';
  148.  
  149.  
  150. 	  int carry = 0;
  151. 	  int num;
  152. 	  int dig;
  153.  
  154. 	  int k =0;
  155. 	  int i;
  156. 	  int j;
  157. 	  int tot_l = 0;
  158. 	  for( i =0; i < strlen(num2); i++){
  159. 	  	 k = 0;
  160. 	  	for(j =0; j < strlen(num1);j++){
  161. 	  		  num = (num1[i]-'0') * (num2[j]-'0')+carry;
  162. 	  		  carry = num/10;
  163. 	  		  dig = num % 10;
  164. 	  		  curr[k] = dig+'0';
  165. 	  		   k++;
  166. 	  		   tot_l++;
  167. 	  	   }
  168.  
  169. 	  	   while(carry > 0){
  170.  
  171. 	  	   	dig = carry %10;
  172. 	  	   	carry = carry/10;
  173. 	  	    curr[k] = dig + '0';
  174. 	  	    k++;
  175. 	  	    tot_l++;
  176.  
  177. 	  	   }
  178.  
  179.  
  180. 	  	 shiftRight(curr,i);
  181.  
  182. 	  	  add(prev,curr);
  183.  
  184. 	  }
  185.  
  186. 	  prev[tot_l] = '\0';
  187. 	  cout << prev;
  188.  
  189.  
  190.  
  191.  
  192.  
  193. }
  194. int main() {
  195.  
  196.  
  197.  
  198. 	int tes;
  199. 	cin >> tes;
  200. 	char arr[30001];
  201.     char num1[10001];
  202.     char num2[10001];
  203.  
  204. 	while(tes--){
  205.  
  206. 		cin >> num1 >> num2;
  207.  
  208. 		reverse(num1);
  209. 		reverse(num2);
  210.  
  211. 		mul(num1, num2);
  212.  
  213.  
  214.  
  215. 	}
  216. 	return 0;
  217.  
  218.  
  219. }
Success #stdin #stdout 0.01s 15240KB
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https://ideone.com/xE0OZV
language:
C++ (gcc 8.3)
created:
6 years ago
visibility:
public

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