HDU-4099Revenge of Fibonacci （高精度加法&&字典树）

传送门

11年上海区域赛题

T组数据，求对于每个数，求最小的n使得该数为斐波那契数列第n位的前缀，若n大于100000，输出-1

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxn = 4e6 + 10;
const int maxsize = 10;

int ch[maxn][maxsize];
int val[maxn];
int A[60];
int B[60];
char s[100];

int T;

struct Trie {
    int sz;
    Trie() {
        sz = 1;
        memset(ch[0], 0, sizeof(ch[0]));
        memset(val, -1, sizeof(val));
    }
    int idx(char c) {return c - '0';}

    void insert(int* a, int len, int v) {
        int u = 0;
        for (int i = len - 1; i >= max(0, len - 40); i--) {
            int c = a[i];
            if (!ch[u][c]) {
                memset(ch[sz], 0, sizeof(ch[sz]));
                ch[u][c] = sz++;
            }
            u = ch[u][c];
            if (val[u] == -1) {
                val[u] = v;
            }
        }
    }

    int find(char* s) {
        int len = strlen(s);
        int u = 0;
        for (int i = 0; i < len; i++) {
            int c = idx(s[i]);
            if (!ch[u][c]) {
                return -1;
            }
            u = ch[u][c];
        }
        return val[u];
    }    

};

Trie Tree;


int main() {
    memset(A, 0, sizeof(A));
    memset(B, 0, sizeof(B));
    B[0] = 1;
    int len1 = 1;
    int len2 = 1;
    for (int n = 0; n < 100000; n++) {
        Tree.insert(B, len2, n);
        int len3 = len2;
        for (int i = 0; i < len3; i++) {
            A[i] += B[i];
            if (A[i] >= 10) {
                A[i] -= 10;
                A[i + 1]++;
            }
        }
        if (A[len3]) len3++;
        if (len3 == 51) {
            len3--;
            for (int i = 0; i < len3; i++) {
                A[i] = A[i + 1];
            }
            A[50] = 0;
            len2--;
            for (int i = 0; i < len2; i++) {
                B[i] = B[i + 1];
            }
            B[len2] = 0;
        }

        swap(A, B);
        len1 = len2;
        len2 = len3;

    }
    scanf("%d", &T);
    for (int i = 1; i <= T; i++) {
        scanf("%s", s);
        printf("Case #%d: %d
", i, Tree.find(s));
    }
    return 0;
}