OJ-Problems-Source/HDOJ/4518_autoAC.cpp

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#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <queue>
using namespace std;
typedef long long LL;
const int N = 600;
LL n;
int bit[20];
LL f[60];
LL dp[15][N];
LL POW[15];
LL seq[60];
LL suf[20];
queue<int>q;
struct Ac_Auto{
int ch[N][10];
int fail[N];
bool flag[N];
int idx, root;
int newnd() {
memset(ch[idx], 0, sizeof (ch[idx]));
flag[idx] = false, fail[idx] = 0;
return idx++;
}
void init() {
idx = 0, root = newnd();
}
void insert(LL x) {
int id = 0;
while (x) bit[id++] = x%10, x/=10;
int p = root;
for (int i = id-1; i >= 0; --i) {
if (!ch[p][bit[i]]) ch[p][bit[i]] = newnd();
p = ch[p][bit[i]];
}
flag[p] = true;
}
void build() {
for (int i = 0; i < 10; ++i) {
if (ch[root][i]) {
q.push(ch[root][i]);
}
}
while (!q.empty()) {
int u = q.front();
q.pop();
for (int i = 0; i < 10; ++i) {
int &v = ch[u][i];
int x = fail[u];
if (v) {
q.push(v);
while (x && !ch[x][i]) x = fail[x];
fail[v] = ch[x][i];
flag[v] = flag[v] || flag[fail[v]];
} else {
v = ch[x][i];
}
}
}
}
void find(LL x) {
int id = 0;
while (x) bit[id++] = x%10, x/=10;
int p = root;
for (int i = id-1; i >= 0; --i) {
p = ch[p][bit[i]];
if (flag[p]) {
cout << "OMG" << endl;
return;
}
}
}
};
Ac_Auto ac;
LL count(int p, int sta, bool bound) {
if (p == 0) return 0;
if (!bound && ~dp[p][sta]) return dp[p][sta];
int y = bound ? bit[p] : 9;
LL sum = 0;
int tsta;
for (int i = 0; i <= y; ++i) {
tsta = ac.ch[sta][i];
if (ac.flag[tsta]) {
if (bound&&i==y) sum += suf[p-1]+1;
else sum += POW[p-1];
continue;
}
sum += ::count(p-1, tsta, bound&&i==y);
}
if (!bound) dp[p][sta] = sum;
return sum;
}
LL cal(LL x) {
int idx = 1;
while (x) suf[idx] = suf[idx-1]+x%10*POW[idx-1], bit[idx++] = x%10, x/=10;
return ::count(idx-1, ac.root, true);
}
void prepare() {
f[1] = 1, f[2] = 1;
for (int i = 3; i <= 55; ++i) {
f[i] = f[i-1] + f[i-2];
}
ac.init();
for (int i = 7; i <= 55; ++i) {
ac.insert(f[i]);
}
ac.build();
POW[0] = 1;
for (int i = 1; i < 15; ++i) POW[i] = POW[i-1] * 10;
memset(dp, 0xff, sizeof (dp));
LL tmp;
for (int i = 2; i <= 55; ++i) {
LL l = 13, r = POW[12], mid;
while (l <= r) {
mid = (l + r) >> 1;
if ((tmp=cal(mid)) < f[i]) l = mid + 1;
else if (tmp > f[i]) r = mid - 1;
else seq[i] = mid, r = mid - 1;
}
}
}
int main() {
prepare();
while (cin >> n, n != -1) {
LL ret = 1LL << 60;
for (int i = 2; i <= 55; ++i) {
LL t = seq[i] - n;
if (t < 0) t = -t;
ret = min(ret, t);
}
cout << ret << endl;
}
return 0;
}