「LYOI2016 Summer」Digits 题解

 1 #include<cstdio>
 2 #include<algorithm>
 3 #include<cmath>
 4 #include<cstring>
 5 
 6 const int MAXN = 100003;
 7 inline void read(long long &x)
 8 {
 9     char ch = getchar(),c = ch;x = 0;
10     while(ch < ‘0‘ || ch > ‘9‘) c = ch,ch = getchar();
11     while(ch <= ‘9‘ && ch >= ‘0‘) x = (x<<1)+(x<<3)+ch-‘0‘,ch = getchar();
12     if(c == ‘-‘) x = -x;
13 }
14 
15 long long n,k,x,tmp,ans,cnt = 1,mod = 1;
16 char s[20];
17 
18 struct NUM
19 {
20     long long a,b;
21 }num[MAXN];
22 
23 long long ksm(long long a,long long b)
24 {
25     long long base = a,r = 1;
26     for(;b;b>>=1)
27     {
28         if(b&1)
29             r = r*base%mod;
30         base = base*base%mod;
31     }
32     return r;
33 }
34 
35 int main()
36 {
37 //    freopen("1.in","r",stdin);
38     read(n),read(k);
39     for(register int i = 1;i <= n;++ i)
40         read(num[i].a),read(num[i].b);
41     for(register int i = 1;i <= k;++ i) 
42         mod *= 10;
43     read(x);
44     for(register int i = 1;i <= n;++ i)
45     {
46         tmp = ksm(x,num[i].b);
47         ans = (ans+tmp*num[i].a%mod)%mod;
48     }
49     tmp = 0;
50     if(ans == 0) s[++tmp] = ‘0‘;
51     else
52         while(ans > 0)
53         {
54             s[++tmp] = (ans%10)+‘0‘;
55             ans /= 10;
56         }
57     for(int i = 0;i < k-tmp;++ i)
58         printf("0\n");
59     for(int i = tmp;i >= 1;-- i)
60         printf("%c\n",s[i]);
61     return 0;
62 }