465 - Overflow

　　这几次写代码都忘记初始化，调了半天，活该啊！

 

C++语言: Codee#25721

001 /*
002 +++++++++++++++++++++++++++++++++++++++
003                 author: chm
004 +++++++++++++++++++++++++++++++++++++++
005 */
006
007 #include <map>
008 #include <set>
009 #include <list>
010 #include <queue>
011 #include <cmath>
012 #include <stack>
013 #include <bitset>
014 #include <cstdio>
015 #include <cctype>
016 #include <string>
017 #include <vector>
018 #include <cassert>
019 #include <cstdlib>
020 #include <cstring>
021 #include <fstream>
022 #include <sstream>
023 #include <iomanip>
024 #include <iostream>
025 #include <algorithm>
026
027 using namespace std;
028
029 FILE*            fin         = stdin;
030 FILE*            fout         = stdout;
031 const int        max_size     = 10086;
032
033 char stra[max_size], strb[max_size];
034 int numa[max_size], numb[max_size];
035 int res[max_size];
036 char resstr[max_size];
037 char inputstr[max_size];
038
039 void convert(char* str, int* num)
040 {
041     int len = strlen(str);
042
043     for(int i = 0, j = len - 1; j >= 0; ++i, --j)    //reverse
044         num[i] = str[j] - '0';
045 }
046
047 bool isvalid(char* stra)
048 {
049     int len = strlen(stra);
050     char max[] = "2147483647";
051
052     // num <= 2147 483 647
053     if(len < 10 ||
054             (len == 10 && strcmp(stra, max) <= 0))    // check length,if len==10
055                                                     // ,compare with INT_MAX
056         return false;
057     else
058         return true;
059 }
060
061 bool anscheck(int idx)
062 {
063     while(idx >= 0 && !res[idx])
064         --idx;
065     for(int i = 0, j = idx; j >= 0; ++i, --j)        //reverse again
066         resstr[i] = res[j] + '0';
067     resstr[idx + 1] = '\0';
068     return isvalid(resstr);
069 }
070
071 bool plusnum(int len1, int len2)
072 {
073     int len = len1 > len2 ? len1 + 1 : len2 + 1;
074
075     int cry = 0;
076     int tmp;
077     for(int i = 0; i < len; ++i)
078     {
079         tmp = cry + numa[i] + numb[i];
080         cry = tmp / 10;
081         res[i] = tmp % 10;
082     }
083     int idx = len - 1;
084     return anscheck(idx);
085 }
086
087 bool multiply(int len1, int len2)
088 {
089     int tmp;
090
091     for(int i = 0; i < len1; ++i)
092         for(int j = 0; j < len2; ++j)
093         {
094             tmp = numa[i] * numb[j] + res[i + j];
095             res[i + j] = tmp % 10;
096             res[i + j + 1] += tmp / 10;
097         }
098     int idx = len1 + len2 + 2;
099     return anscheck(idx);
100 }
101
102 void discardprezero(char* str)            //delete precede zeros like 00000000001
103 {
104     char* ptr = str;
105     char* tmp = str;
106     while(*ptr == '0')
107         ++ptr;
108     if(ptr != str)
109         while(*str++ = *ptr++);
110     if(*tmp == '\0')
111     {
112         tmp[0] = '0';
113         tmp[1] = '\0';
114     }
115 }
116
117 int main()
118 {
119 #ifndef ONLINE_JUDGE
120     freopen("c:\\in.txt", "r", stdin);
121     fout = fopen("c:\\garage\\out.txt", "w");
122 #endif
123
124     char op[2];
125     int len1, len2;
126     bool flarge, slarge, rlarge;
127
128     while(fgets(inputstr, sizeof(inputstr), stdin))
129     {
130
131         fprintf(fout, "%s", inputstr);
132         sscanf(inputstr, "%s %s %s\n", stra, op, strb);
133
134         memset(numa,0,sizeof(stra));
135         memset(numb,0,sizeof(strb));
136         memset(res, 0, sizeof(res));
137
138         discardprezero(stra);
139         len1 = strlen(stra);
140         convert(stra, numa);
141         flarge = isvalid(stra);
142
143         discardprezero(strb);
144         len2 = strlen(strb);
145         convert(strb, numb);
146         slarge = isvalid(strb);
147
148         if(op[0] == '+')
149             rlarge = plusnum(len1, len2);
150         else
151             rlarge = multiply(len1, len2);
152
153         if(flarge)
154             fprintf(fout, "first number too big\n");
155         if(slarge)
156             fprintf(fout, "second number too big\n");
157         if(rlarge)
158             fprintf(fout, "result too big\n");
159     }
160
161 #ifndef ONLINE_JUDGE
162     fclose(fout);
163     system("c:\\garage\\check.exe");
164     system("notepad c:\\garage\\out.txt");
165 #endif
166     return 0;
167 }