UVA 10367 - Equations(数论+模拟）

来源：互联网发布：淘宝刷好评兼职要会费编辑：程序博客网时间：2024/06/05 08:55

题目链接：10367 - Equations

题意:题意很简单，给定两个二元一次方程，求x，y，如果矛盾或者求不出来就输出dont know

思路：模拟。。。恶心题。。很多细节要注意

代码:

#include <stdio.h>#include <string.h>#include <stdlib.h>#define INF 0x3f3f3f3fint t;char str[1005];struct Exp {    long long x, y, c;    Exp() {x = 0; y = 0; c = 0;}} e[2];long long gcd(long long a, long long b) {    if (b == 0) return a;    return gcd(b, a % b);}Exp tra(char *str) {    Exp ans;    int n = strlen(str);    long long sum = 0, flag = 1, f = 1;    str[n] = ' ';    for (int i = 0; i <= n; i++) {if (str[i] == '=') {    f = -1;    continue;}if (str[i] >= '0' && str[i] <= '9') {    sum = sum * 10 + str[i] - '0';}else if (str[i] == '-')    flag = -flag;else if (str[i] == '+')    flag = 1;else if (str[i] == 'x') {    if (sum == 0) sum = 1;    ans.x += f * flag * sum;    sum = 0;    flag = 1;}else if (str[i] == 'y') {    if (sum == 0) sum = 1;    ans.y += f * flag * sum;    sum = 0;    flag = 1;}else {    if (sum != 0) {ans.c -= f * flag * sum;sum = 0;flag = 1;    }}    }    return ans;}void init() {    memset(e, 0, sizeof(e));    getchar();    gets(str);    e[0] = tra(str);    gets(str);    e[1] = tra(str);}struct Ans {    long long zi, mu, f, vis;    void init() {zi = 0; mu = 0; f = 1; vis = 0;    }    void tra() {if (zi < 0) {    zi = -zi;    f *= -1;}if (mu < 0) {    mu = -mu;    f *= -1;}long long g = gcd(zi, mu);if (g != 0) {    zi /= g; mu /= g;}    }    void put() {if (vis) printf("don't know\n");else if (zi == 0) printf("0\n");else if (mu == 1) printf("%lld\n", f * zi);else printf("%lld/%lld\n", f * zi, mu);    }} ansx, ansy;void solve() {    ansx.init(); ansy.init();    int g0 = gcd(gcd(abs(e[0].x), abs(e[0].y)), abs(e[0].c));    int g1 = gcd(gcd(abs(e[1].x), abs(e[1].y)), abs(e[1].c));    if (g0 != 0) {e[0].x /= g0; e[0].y /= g0; e[0].c /= g0;    }    if (g1 != 0) {e[1].x /= g1; e[1].y /= g1; e[1].c /= g1;    }    ansx.zi = e[0].c * e[1].y - e[1].c * e[0].y;    ansx.mu = e[0].x * e[1].y - e[1].x * e[0].y;    ansy.zi = e[0].c * e[1].x - e[1].c * e[0].x;    ansy.mu = e[0].y * e[1].x - e[0].x * e[1].y;    ansx.tra();    ansy.tra();    if (e[0].x == 0 && e[0].y == 0 && e[0].c != 0) {ansx.vis = 1; ansy.vis = 1; return;    }    if (e[1].x == 0 && e[1].y == 0 && e[1].c != 0) {ansx.vis = 1; ansy.vis = 1; return;    }    if (e[0].x == 0 && e[0].y == 0 && e[1].x == 0 && e[1].y == 0) {ansx.vis = 1; ansy.vis = 1; return;    }    if (e[0].x == 0 && e[1].x == 0) {ansx.vis = 1;if (e[0].c * e[1].y != e[1].c * e[0].y)    ansy.vis = 1;else {    if (e[0].y != 0) {ansy.zi = e[0].c;ansy.mu = e[0].y;    }    if (e[1].y != 0) {ansy.zi = e[1].c;ansy.mu = e[1].y;    }    ansy.tra();}return;    }    if (e[0].y == 0 && e[1].y == 0) {ansy.vis = 1;if (e[0].c * e[1].x != e[1].c * e[0].x)    ansx.vis = 1;else {    if (e[0].x != 0) {ansx.zi = e[0].c;ansx.mu = e[0].x;    }    if (e[1].x != 0) {ansx.zi = e[1].c;ansx.mu = e[1].x;    }    ansx.tra();}return;    }    if (ansx.mu == 0 && ansy.mu == 0) {if (!ansx.vis && !ansy.vis) {    ansx.vis = 1;    ansy.vis = 1;    return;}    }}int main() {    scanf("%d", &t);    while (t--) {init();solve();ansx.put();ansy.put();if (t) printf("\n");    }    return 0;}

1 0