With given integers a,b,c, you are asked to judge whether the following statement is true: "For any x, if a?x2+b?x+c=0, then x is an integer."
标签：else als cas print include number stdio.h nbsp 描述
时间限制: 2 秒 内存限制: 128 MB | 提交: 277 解决: 44
With given integers a,b,c, you are asked to judge whether the following statement is true: "For any x, if a?x2+b?x+c=0, then x is an integer."
The first line contains only one integer T(1≤T≤2000), which indicates the number of test cases.
For each test case, there is only one line containing three integers a,b,c(?5≤a,b,c≤5).
or each test case, output “YES” if the statement is true, or “NO” if not.
3 1 4 4 0 0 1 1 3 1
YES YES NO 题意：判断"For any x, if a?x2+b?x+c=0, then x is an integer."是否成立
前件：For any x, if a?x2+b?x+c=0成立 （方程有解）
后件：then x is an integer.成立 （解是整数）
离散数学 p 为前件 q 为后件 的蕴含式 只有前件为 T 后件 为 F 时事件才为 F
#include <cstdio> #include <cmath> bool judge(int a , int b , int c){ if(a==0){ if(b==0){ if(c==0){ return false ; // 此时x可以取 任何值 不成立 } return true ; } else if(c%b==0){ return true ; } return false ; // } double d = b*b - 4 * a * c ; int D = (int)sqrt(d) ; if(d < 0){ return true ; } if(fabs(D - sqrt(d)) < 0.00000001){ if((0-b+D)%(2*a)==0 ){ if((0-b-D)%(2*a)==0) return true ; } } return false ; } int main(){ int t ; int a , b , c ; scanf("%d" , &t) ; while(t--){ scanf("%d%d%d" , &a , &b , &c) ; if(judge(a , b , c)){ printf("YES\n") ; } else { printf("NO\n") ; } } return 0 ; }
#include<stdio.h> #include<math.h> int main(void) { int T, a, b, c; double x; scanf("%d", &T); while(T--) { scanf("%d%d%d", &a, &b, &c); if(a==0 && b==0 && c==0) printf("NO\n"); else if(a==0 && b==0) printf("YES\n"); else if(a==0) { if(c%b==0) printf("YES\n"); else printf("NO\n"); } else if(b*b-4*a*c<0) printf("YES\n"); else { x = sqrt(1.0*b*b-4*a*c); if((-b+x)/(2*a)-(int)(-b+x)/(2*a)==0 && (-b-x)/(2*a)-(int)(-b-x)/(2*a)==0) printf("YES\n"); else printf("NO\n"); } } return 0; }
2017年ACM第八届山东省赛F题：quadratic equation（离散数学蕴含式）
标签：else als cas print include number stdio.h nbsp 描述
原文地址：http://www.cnblogs.com/yi-ye-zhi-qiu/p/7631563.html
