TOJ-1409 - Equations

#include <cstdio>#include <iostream>#include <algorithm>#include <cstdlib>#include <cstring>#include <string>#include <map>#include <cctype>using namespace std;char s1[800], s2[800];int num[2][5]; int gcd(int a, int b){if (a < b) swap(a, b);while (b) {int tmp = a % b; a = b; b = tmp;} return a;}int cal(char *s, int xx, int f, int ff){int t = 0, k = 1, x = xx;bool flag = 0;if (x == f - 1) return 1;while (x >= f && isdigit(s[x])) {if (isdigit(s[x])) flag = 1;t += k * (s[x] - '0'), k *= 10; x--;}if (t == 0 && ff && !flag) t = 1;while (x >= f && (s[x] == '+' || s[x] == '-')) {if (s[x] == '-') t *= -1; x--;}return t;}void change(char *s){int cnt = 0, len = strlen(s);for (int i = 0; i < len; i++)if (s[i] != ' ') s[cnt++] = s[i];for (int i = cnt; i < len; i++)s[i] = '\0';}void make(char *s, int line){int len = strlen(s), pos;for (int i = 0; i < len; i++) {if (s[i] == '+' || s[i] == '-' || s[i] == '='){int j = i - 1;if (s[j] == 'x')num[line][0] += cal(s, j - 1, 0, 1);else if (s[j] == 'y')num[line][1] += cal(s, j - 1, 0, 1);else if (isdigit(s[j]))num[line][2] -= cal(s, j, 0, 0);}if (s[i] == '=') { pos = i + 1; break; }}for (int i = pos; i <= len; i++){if (s[i] == '+' || s[i] == '-' || i == len) {int j = i - 1; if (s[j] == 'x') num[line][0] -= cal(s, j - 1, pos, 1);else if (s[j] == 'y')num[line][1] -= cal(s, j - 1, pos, 1);else if (isdigit(s[j]))num[line][2] += cal(s, j, pos, 0);}}}void impos(){printf("don't know\n");}void print(int x, int y, int z){if (z != 0) impos();else if (y == 0) printf("0\n");else {int ttt = gcd(abs(x), abs(y));if (x * y < 0 && abs(x) != ttt) printf("-%d/%d\n", abs(y)/ttt, abs(x)/ttt);else if (x * y < 0 && abs(x) == ttt) printf("-%d\n", abs(y)/ttt);else if (x * y > 0 && abs(x) != ttt) printf("%d/%d\n", abs(y)/ttt, abs(x)/ttt);else printf("%d\n", abs(y)/ttt);}}void solve(){int a, b, c, aa, bb, cc;a = num[0][0]; b = num[0][1]; c = num[0][2]; aa = num[1][0]; bb = num[1][1]; cc = num[1][2];if ((!a && !b && !aa && !bb)||(!a && !b && aa && bb)||(a && b && !aa && !bb))impos(), impos();else if (a && !b && !aa && !bb) print(a, c, cc), impos();else if (!a && b && !aa && !bb) impos(), print(b, c, cc);else if (!a && !b && aa && !bb) print(aa, cc, c), impos();else if (!a && !b && !aa && bb) impos(), print(bb, cc, c);else if (a && !b && aa && !bb) {if (a * cc == aa * c)  print(a, c, 0), impos();else impos(), impos();}else if (!a && b && !aa && bb) {if (b * cc == bb * c)  impos(), print(b, c, 0);else impos(), impos();}else if (a && !b && !aa && bb) print(a, c, 0), print(bb, cc, 0);else if (!a && b && aa && !bb) print(b, c, 0), print(aa, cc, 0);else if (!a && b && aa && bb) print(aa * b, cc * b - c * bb, 0), print(b, c, 0);else if (a && !b && aa && bb) print(a, c, 0), print(bb * a, cc * a - c * aa, 0);else if (a && b && !aa && bb) print(a * bb, c * bb - cc * b, 0), print(bb, cc, 0);else if (a && b && aa && !bb) print(aa, cc, 0), print(b * aa, c * aa - cc * a, 0);else{if (a * bb == b * aa) impos(), impos();else print(a * bb - aa * b, c * bb - cc * b, 0), print(b * aa - bb * a, c * aa - cc * a, 0);}}int main(){int cas, flag, count = 0;cin >> cas;while (cas--){getchar();gets(s1); gets(s2);memset(num, 0, sizeof(num));change(s1), change(s2);make(s1, 0); make(s2, 1);solve();if (cas) printf("\n");} return 0; }