1005 大数加法

基准时间限制：1 秒空间限制：131072 KB　　

给出2个大整数A,B，计算A+B的结果。

Input

第1行：大数A 第2行：大数B (A,B的长度 <= 10000 需注意：A B有可能为负数）

Output

输出A + B

Input示例

68932147586 468711654886

Output示例

537643802472

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 
 5 char A[10005];
 6 char B[10005];
 7 int fa, fb; 
 8 
 9 void swap(char* a, int i, int j)
10 {
11     char t = a[i] - '0';
12     a[i] = a[j] - '0';
13     a[j] = t;
14 }
15 
16 void add(char* a, char* b)
17 {
18     int la, lb, i, j, s, l, c=0;
19     la = strlen(a);
20     lb = strlen(b);
21     
22     for (i = fa, j = la-1; i <= j; ++i, --j) swap(a, i, j);
23     for (i = fb, j = lb-1; i <= j; ++i, --j) swap(b, i, j);
24     
25     for (i = fa; i<la || i<lb; ++i) {
26         s = a[i] + b[i] + c;
27         c = s / 10;
28         a[i] = s % 10;
29     }
30     a[i] = c;
31     l = c ? i : i-1;
32     if (fa) printf("-");
33     for (i = l; i >= fa; --i) printf("%d", a[i]);
34 }
35 
36 int cmp(char* a, char* b)
37 {
38     int i;
39     int la = strlen(a);
40     int lb = strlen(b);
41     
42     if (la-fa > lb-fb)
43         return 1;
44     else if (la-fa < lb-fb)
45             return 0;
46     else {
47         for (i = 0; i < la && a[i+fa]==b[i+fb]; ++i);
48         return a[i+fa] > b[i+fb];
49     }
50 }
51 
52 void minus(char* a, char* b)
53 {
54     char* tmp;
55     int la, lb, i, j, s, l, t, c=0;
56     
57     if (!cmp(a, b)) {
58         tmp = a; a = b; b = tmp;
59         t = fa; fa = fb; fb = t;
60     }
61     la = strlen(a);
62     lb = strlen(b);
63     for (i = fa, j = la-1; i <= j; ++i, --j) swap(a, i, j);
64     for (i = fb, j = lb-1; i <= j; ++i, --j) swap(b, i, j);
65     l = -1;
66     for (i = 0; i+fa < la; ++i) {
67         s = a[i+fa] - b[i+fb] - c >= 0 ? 0 : 1;
68         a[i+fa] = (a[i+fa] - b[i+fb] - c + 10) % 10;
69         l = a[i+fa] ? i+fa : l;
70         c = s;
71     }
72     if (l < 0) printf("0");
73     else {
74         if (fa) printf("-");
75         for (i = l; i >= fa; --i) printf("%d", a[i]);
76     }
77 }
78 
79 int main ()
80 {
81     scanf("%s%s", A, B);
82     fa = ('-' == A[0]);
83     fb = ('-' == B[0]);
84     if (fa^fb)
85         minus(A, B);
86     else
87         add(A, B);
88     return 0;
89 }