1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165
| #include <stdlib.h> #include <cstring> #include <iostream>
using namespace std;
#define M 100 char string_largeInteger_A[1000]; char string_largeInteger_B[1000];
typedef struct _Node { int data[M]; int length; int pow; }Node, *pNode;
void Multiplie(pNode pa, pNode pb, pNode ans); void Decompose(pNode src, pNode des, int Start, int length); void Add(pNode pa, pNode pb, pNode ans);
int main() { Node answer, largeInteger_A, largeInteger_B; int digit; cout << "输入大整数 a: " << endl; cin >> string_largeInteger_A; cout << "输入大整数 b: " << endl; cin >> string_largeInteger_B;
digit = 0; largeInteger_A.length = strlen(string_largeInteger_A); for (int i = largeInteger_A.length - 1; i >= 0; i--) { largeInteger_A.data[digit++] = string_largeInteger_A[i] - '0'; } largeInteger_A.pow = 0;
digit = 0; largeInteger_B.length = strlen(string_largeInteger_B); for (int i = largeInteger_B.length - 1; i >= 0; i--) { largeInteger_B.data[digit++] = string_largeInteger_B[i] - '0'; } largeInteger_B.pow = 0;
Multiplie(&largeInteger_A, &largeInteger_B, &answer); cout << "最终结果是:"; for (int i = answer.length - 1; i >= 0; i--) cout << answer.data[i]; cout << endl; return 0; }
void Multiplie(pNode multiplierA, pNode multiplierB, pNode answer) { Node multiplierA_highDigit, multiplierA_lowDigit, multiplierB_highDigit, multiplierB_lowDigit; Node temp_AhBh, temp_AhBl, temp_AlBh, temp_AlBl, temp_answer; pNode swap_temp; int bisection_A, bisection_B; int single_digit, answer_digit, remainder;
remainder = 0; bisection_A = multiplierA->length >> 1; bisection_B = multiplierB->length >> 1;
if (bisection_A == 0 || bisection_B == 0) { if (bisection_A == 0) { swap_temp = multiplierA; multiplierA = multiplierB; multiplierB = swap_temp; } answer->pow = multiplierA->pow + multiplierB->pow;
single_digit = multiplierB->data[0]; for (answer_digit = 0; answer_digit < multiplierA->length; answer_digit++) { answer->data[answer_digit] = (multiplierA->data[answer_digit] * single_digit + remainder) % 10; remainder = (multiplierA->data[answer_digit] * single_digit + remainder) / 10; } if (remainder) answer->data[answer_digit++] = remainder; answer->length = answer_digit; return; }
Decompose(multiplierA, &multiplierA_highDigit, bisection_A, multiplierA->length - bisection_A); Decompose(multiplierA, &multiplierA_lowDigit, 0, bisection_A); Decompose(multiplierB, &multiplierB_highDigit, bisection_B, multiplierB->length - bisection_B); Decompose(multiplierB, &multiplierB_lowDigit, 0, bisection_B);
Multiplie(&multiplierA_highDigit, &multiplierB_highDigit, &temp_AhBh); Multiplie(&multiplierA_highDigit, &multiplierB_lowDigit, &temp_AhBl); Multiplie(&multiplierA_lowDigit, &multiplierB_highDigit, &temp_AlBh); Multiplie(&multiplierA_lowDigit, &multiplierB_lowDigit, &temp_AlBl);
Add(&temp_AlBh, &temp_AlBl, answer); Add(&temp_AhBl, answer, &temp_answer); Add(&temp_AhBh, &temp_answer, answer); }
void Decompose(pNode src, pNode des, int Start, int length) { for (int i = Start, j = 0; i < Start + length; i++, j++) { des->data[j] = src->data[i]; } des->length = length; des->pow = Start + src->pow; }
void Add(pNode augend, pNode addend, pNode answer) { pNode swap_temp;
int augend_digit, addend_digit, max_digit; int remainder; int augendx_temp, addendx_temp; int answer_digit; int pow_difference;
if (augend->pow < addend->pow) { swap_temp = augend; augend = addend; addend = swap_temp; }
answer->pow = addend->pow;
augend_digit = augend->pow + augend->length; addend_digit = addend->pow + addend->length; max_digit = (augend_digit > addend_digit) ? augend_digit : addend_digit ;
pow_difference = augend->pow - addend->pow; remainder = 0; for (answer_digit = 0; answer_digit < max_digit - answer->pow; answer_digit++) { if (answer_digit < pow_difference || answer_digit >= augend->length + pow_difference) augendx_temp = 0; else augendx_temp = augend->data[answer_digit - pow_difference]; if (answer_digit < addend->length) addendx_temp = addend->data[answer_digit]; else addendx_temp = 0; answer->data[answer_digit] = (augendx_temp + addendx_temp + remainder) % 10; remainder = (augendx_temp + addendx_temp + remainder) / 10; } if (remainder) answer->data[answer_digit++] = remainder; answer->length = answer_digit; }
|