省选班Day1
Naughty Fairies
虽然我的做法T了，但是那应该让高精度背锅（多了个N就T了）
大概和老师算法差不多？（为什么我的这么不像dp）
首先将数转换为二进制
那能不能直接贪心？
发现我们如果是目标的前缀，那么只需要把*2和+1/0交替就行了
Is that right?
hack: 1111 11111
因为有了 (-1) 操作，发现贪心不能保证正确性，GG了
但是这同样启发我们成为目标的前缀和前缀 (+1) 同样重要
这样就可以 (DP) 了（是不是很神奇）
(dp[i][j]) 表示当前处理到第 (i) 位 是前缀或前缀 (+1) )
转移：
[if ~(b[i]=0)~ dp[i][0]=min(dp[i-1][0]+1,dp[i-1][1]+2),dp[i][1]=min(dp[i-1][0]+2,dp[i-1][1]+2)\
else ~dp[i][0]=min(dp[i-1][0]+2,dp[i-1][1]+2), dp[i][1]=min(dp[i-1][0]+2,dp[i-1][1]+1)\
]
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
#define cls(a) memset(a, 0, sizeof(a))
#define rise(i, a, b) for (int i = a; i <= b; i++)
#define fall(i, a, b) for (int i = a; i >= b; i--)
const int base = 1e9;
char a[600];
bool ined, flag;
int cnt, cntt, ep;
void init() {
ined = false;
cnt = 0;
while (true) {
a[cnt] = getchar();
if (a[cnt] >= '0' && a[cnt] <= '9') {
ined = true;
cnt++;
} else if (ined)
break;
}
a[cnt] = ' ';
cnt--;
}
struct point {
int num[60], len;
point() { clear(); }
void clear() {
len = 1;
cls(num);
}
void out(int x) {
printf("%d", num[len]);
fall(i, len - 1, 1) printf("%09d", num[i]);
if (x)
putchar('
');
else
putchar(' ');
}
void in() {
init();
cntt = 0;
ep = 1;
clear();
fall(i, cnt, 0) {
if (cntt == 9) {
cntt = 0;
len++;
ep = 1;
}
cntt++;
num[len] += (int)(a[i] - '0') * ep;
ep *= 10;
}
while (len > 1 && num[len] == 0) len--;
}
void inc() {
num[1]++;
rise(i, 1, len) {
if (num[i] >= base) {
num[i + 1]++;
num[i] -= base;
} else
break;
}
if (num[len + 1] == 1)
len++;
}
void dec(int x) {
num[1] -= x;
rise(i, 1, len) {
if (num[i] < 0) {
num[i + 1]--;
num[i] += base;
} else
break;
}
if (num[len] == 0)
len--;
}
void divid() {
fall(i, len, 1) {
num[i - 1] += (num[i] & 1) * base;
num[i] >>= 1;
}
if (num[len] == 0)
len--;
}
point &operator=(const point &);
point operator-(const point &) const;
point operator+(const point &) const;
point(const int);
bool operator>(const point &p) const;
bool operator<(const point &p) const;
bool operator==(const point &p) const;
} n, m, one, zero, two, now[3], tmp[5], nv[3], tv[5], ans;
point &point ::operator=(const point &p) {
clear();
len = p.len;
rise(i, 1, len) num[i] = p.num[i];
return *this;
}
point point ::operator+(const point &p) const {
point ret = *this;
int l = max(ret.len, p.len);
rise(i, 1, l) {
ret.num[i] += p.num[i];
if (ret.num[i] >= base) {
ret.num[i + 1]++;
ret.num[i] -= base;
}
}
if (ret.num[l + 1] > 0)
l++;
ret.len = l;
return ret;
}
point point ::operator-(const point &p) const {
point ret = *this;
if (ret > p) {
rise(i, 1, ret.len) {
ret.num[i] -= p.num[i];
if (ret.num[i] < 0) {
ret.num[i] += base;
ret.num[i + 1]--;
}
}
while (ret.len > 1)
if (ret.num[ret.len] == 0)
ret.len--;
else
break;
return ret;
}
if (ret == p)
return zero;
if (ret < p) {
point tmp = ret;
ret = p;
rise(i, 1, ret.len) {
ret.num[i] -= tmp.num[i];
if (ret.num[i] < 0) {
ret.num[i] += base;
ret.num[i + 1]--;
}
}
while (ret.len > 1)
if (ret.num[ret.len] == 0)
ret.len--;
else
break;
return ret;
}
}
point::point(const int b) {
clear();
num[1] = b;
}
bool point::operator==(const point &p) const {
if (len != p.len)
return false;
fall(i, len, 1) if (num[i] != p.num[i]) return false;
return true;
}
bool point::operator>(const point &p) const {
if (len > p.len)
return true;
if (len < p.len)
return false;
fall(i, len, 1) {
if (num[i] > p.num[i])
return true;
if (num[i] < p.num[i])
return false;
}
return false;
}
bool point::operator<(const point &p) const {
if (len < p.len)
return true;
if (len > p.len)
return false;
fall(i, len, 1) {
if (num[i] < p.num[i])
return true;
if (num[i] > p.num[i])
return false;
}
return false;
}
int main() {
one = point(1);
zero = point(0);
two = point(2);
int cnt = 1;
while (true) {
m.in();
n.in();
if (n == zero && m == zero)
break;
if (n > m || n == m) {
(n - m).out(1);
continue;
}
now[1] = m;
ans = m - n;
cnt = 1;
cntt = 0;
while (cnt) {
rise(i, 1, cnt) {
if (ans > now[i] - n + nv[i])
ans = now[i] - n + nv[i];
if (now[i].num[1] % 2 == 0) {
flag = 0;
rise(j, 1, cntt) if (now[i] == tmp[j]) {
if (nv[i] < tv[j])
tv[j] = nv[i];
flag = true;
}
if (!flag) {
tmp[++cntt] = now[i];
tv[cntt] = nv[i];
}
} else {
nv[i].inc();
flag = false;
now[i].inc();
rise(j, 1, cntt) if (now[i] == tmp[j]) {
if (nv[i] < tv[j])
tv[j] = nv[i];
flag = true;
}
if (!flag) {
tmp[++cntt] = now[i];
tv[cntt] = nv[i];
}
if (now[i] > two) {
flag = false;
now[i].dec(2);
rise(j, 1, cntt) if (now[i] == tmp[j]) {
if (nv[i] < tv[j])
tv[j] = nv[i];
flag = true;
}
if (!flag) {
tmp[++cntt] = now[i];
tv[cntt] = nv[i];
}
}
}
now[i].clear();
nv[i].clear();
}
cnt = 0;
rise(i, 1, cntt) {
if ((tmp[i].len > 1 || tmp[i].num[1] > 2) && tmp[i] > n) {
tmp[i].divid();
nv[++cnt] = tv[i] + one;
now[cnt] = tmp[i];
}
tmp[i].clear();
tv[i].clear();
}
cntt = 0;
}
ans.out(1);
}
return 0;
}