BYR Achieve · 镜像论坛

遇到一个编程题目，出现了问题，希望麻烦大家看看，帮忙找出错误。杭电ACM月赛题目及源程序题目： The Diophantine Equation Time Limit: 1000/500 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1142 Accepted Submission(s): 149 Problem Description We will consider a linear Diaphonic equation here and you are to find out whether the equation is solvable in non-negative integers or not. Easy, is not it? Input There will be multiple cases. Each case will consist of a single line expressing the Diophantine equation we want to solve. The equation will be in the form ax + by = c. Here a and b are two positive integers expressing the co-efficient of two variables x and y. There are spaces between: 1. “ax” and ‘+’ 2. ‘+’ and “by” 3. “by” and ‘=’ 4. ‘=’ and “c” c is another integer that express the result of ax + by. -1000000<c<1000000. All other integers are positive and less than 100000. Note that, if a=1 then ‘ax’ will be represented as ‘x’ and same for by. Output You should output a single line containing either the word “Yes.” or “No.” for each input cases resulting either the equation is solvable in non-negative integers or not. An equation is solvable in non-negative integers if for non-negative integer value of x and y the equation is true. There should be a blank line after each test cases. Please have a look at the sample input-output for further clarification. Sample Input 2x + 3y = 1015x + 35y = 67x + y = 0 Sample Output Yes.No.Yes.HINT: The first equation is true for x = 2, y = 2. So, we get, 2*2 + 3*2=10.Therefore, the output should be “Yes.” 我的程序： #include<stdio.h> void main() { int a=0,b=0,c=0; int i,j,l=0; int flag=0,x; char f,z[1000]; while(1) { f=getchar(); z[l]=f; if(z[l]==10) break; l++; } for(i=0;i<l;i++) { if(z[i]=='x'&&i==0) a=1; if(z[i]=='x'&&i!=0) { for(j=0;j<i;j++) { a=a*10+(z[j]-48); } } if(z[i]=='x') x=i; } for(i=0;i<l;i++) { if(z[i]=='y'&&z[i-1]==' ') b=1; if(z[i]=='y'&&z[i-1]!=' ') { for(j=x+4;j<i;j++) { b=b*10+(z[j]-48); } } } for(i=0;i<l;i++) { if(z[i]=='='&&z[i+1]==' ') { if(z[i+2]!='-') { for(j=i+2;j<l;j++) { c=c*10+(z[j]-48); } } if(z[i+2]=='-') { for(j=i+3;j<l;j++) { c=c*10+(z[j]-48); } c=-c; } } } if(c>=0) { for(i=0;i<=c/a;i=i++) { for(j=0;j<=(c-a*i)/b;j=j++) { if(a*i+b*j==c) { flag=1; goto last; } } } } last: if(flag==1) printf("Yes.\n\n"); else printf("No.\n\n"); } 麻烦看看，有什么错误？比赛系统提示是“time limit exceeded”。

求助：一道杭电ACM月赛题目