Hdu 1250 Hat's Fibonacci

唔，bign类高精度还是蛮好用的。

#include <iostream>#include <cstdlib>#include <cstdio>#include <cstring>#include <string>using namespace std;const int MAXN = 2010;int n;struct bign{int len, s[MAXN];bign (){memset(s, 0, sizeof(s));len = 1;}bign (int num) {*this = num;}bign (const char *num) { *this = num;}bign operator = (const char *num){len = strlen(num);for(int i = 0; i < len; i++) s[i] = num[len-i-1] - '0';return *this;}bign operator = (int num){char s[MAXN];sprintf(s, "%d", num);*this = s;return *this;}bign operator +(const bign &b) const{bign c;c.len = 0;for(int i = 0, g = 0; g || i < max(len, b.len); i++){int x = g;if(i < len) x += s[i];if(i < b.len) x += b.s[i];c.s[c.len++] = x%10;g = x / 10;}return c;}bool operator < (const bign &b) const{if(len != b.len) return len < b.len;for(int i = len-1; i >= 0; i--){if(s[i] != b.s[i]) return s[i] < b.s[i];}return false;}void print(){for(int i = len-1; i >= 0; i--){printf("%d", s[i]);}printf("\n");}};void solve(){if(n == 1) { printf("1\n"); return ;}if(n == 2) { printf("1\n"); return ;}if(n == 3) { printf("1\n"); return ;}if(n == 4) { printf("1\n"); return ;}bign f1 = 1, f2 = 1, f3 = 1, f4 = 1, f5 = 1;for(int i = 5; i <= n; i++){f5 = f1+f2+f3+f4;f1 = f2;f2 = f3;f3 = f4;f4 = f5;}f5.print();}int main(){while(~scanf("%d", &n)){solve();}return 0;}