Andrew Stankevich's Contest (1)

Andrew Stankevich's Contest (1)

打一半出门了，回来才补完了。。。各种大数又不能上java。。也是蛋疼无比

A：依据置换循环节非常easy得出要gcd(x, n) = 1而且x <= n / 2，那么把相应几种情况的最大值考虑一下就可以，各自是n % 2 = 1为n / 2, n % 4 = 0为n / 2 - 1，n % 4 = 2为n / 2 - 2

B：限制下限的最大流，建模方法为原来容量变成c - l，然后源点连到每一个点的下限和为正，每一个点下限和为负连到汇点，跑一下最大流，假设源点流出的所有满流就是有解，然后输出的时候仅仅要把相应的自由流加上下限就可以

C：贪心，从叶子结点不断往上推，一有合适就用掉，然后把父结点标记一下用来推断就可以

D：就简单的矩阵相乘，因为要考虑复杂度，所以能够先算出没排的和，然后每一个位置分别乘上相应那排再累加就可以

E：矩阵高速幂，把两两关系确立后，建立矩阵跑一下高速幂就可以

F：几何题，推断有限视角和是否会形成-2pi，利用spfa判负环就可以

G：LIS，先按x从小到大，再按y从大到小排序，这样对y做lis就是答案，因为要输出路径，所以开一个dp数组记录下每一个位置的答案，然后在扫一遍随意输出一种方案就可以

H：高斯消元，和大白书上例题差点儿相同，全然平方数的每一个因子必定是偶数，这样就能够建立异或方程，然后计算出自由便元个数x，那么答案就是2^x - 1

代码：

A:

#include <cstdio>
#include <cstring>
#include <iostream>
 
using namespace std;
typedef long long ll;
const int MAXN = 2005;
 
struct bign {
    int len;
    ll num[MAXN];
 
    bign () {
        len = 0;
        memset(num, 0, sizeof(num));
    }
    bign (ll number) {*this = number;}
    bign (const char* number) {*this = number;}
 
    void DelZero ();
    void Put ();
 
    void operator = (ll number);
    void operator = (char* number);
 
    bool operator <  (const bign& b) const;
    bool operator >  (const bign& b) const { return b < *this; }
    bool operator <= (const bign& b) const { return !(b < *this); }
    bool operator >= (const bign& b) const { return !(*this < b); }
    bool operator != (const bign& b) const { return b < *this || *this < b;}
    bool operator == (const bign& b) const { return !(b != *this); }
 
    void operator ++ ();
    void operator -- ();
    bign operator + (const int& b);
    bign operator + (const bign& b);
    bign operator - (const int& b);
    bign operator - (const bign& b);
    bign operator * (const ll& b);
    bign operator * (const bign& b);
    bign operator / (const ll& b);
    //bign operator / (const bign& b);
    int operator % (const int& b);
};
 
/*Code*/
 
char str[2005];
 
int main() {
    while (~scanf("%s", str)) {
        bign sb;
        sb = str;
        bign ans;
        if (sb % 2) ans = sb / 2;
        else if (sb % 4 == 0) ans = sb / 2 - 1;
        else ans = sb / 2 - 2;
        ans.Put();
        printf("
");
    }
    return 0;
}
 
 
 
/*********************************************/
 
void bign::DelZero () {
    while (len && num[len-1] == 0)
        len--;
 
    if (len == 0) {
        num[len++] = 0;
    }
}
 
void bign::Put () {
    for (int i = len-1; i >= 0; i--)
        printf("%lld", num[i]);
}
 
void bign::operator = (char* number) {
    len = strlen (number);
    for (int i = 0; i < len; i++)
        num[i] = number[len-i-1] - '0';
    DelZero ();
}
 
void bign::operator = (ll number) {
 
    len = 0;
    while (number) {
        num[len++] = number%10;
        number /= 10;
    }
 
    DelZero ();
}
 
bool bign::operator < (const bign& b) const {
    if (len != b.len)
        return len < b.len;
    for (int i = len-1; i >= 0; i--)
        if (num[i] != b.num[i])
            return num[i] < b.num[i];
    return false;
}
 
void bign::operator ++ () {
    int s = 1;
 
    for (int i = 0; i < len; i++) {
        s = s + num[i];
        num[i] = s % 10;
        s /= 10;
        if (!s) break;
    }
 
    while (s) {
        num[len++] = s%10;
        s /= 10;
    }
}
 
void bign::operator -- () {
    if (num[0] == 0 && len == 1) return;
 
    int s = -1;
    for (int i = 0; i < len; i++) {
        s = s + num[i];
        num[i] = (s + 10) % 10;
        if (s >= 0) break;
    }
    DelZero ();
}
 
bign bign::operator + (const int& b) {
    bign a = b;
    return *this + a;
}
 
bign bign::operator + (const bign& b) {
    int bignSum = 0;
    bign ans;
 
    for (int i = 0; i < len || i < b.len; i++) {
        if (i < len) bignSum += num[i];
        if (i < b.len) bignSum += b.num[i];
 
        ans.num[ans.len++] = bignSum % 10;
        bignSum /= 10;
    }
 
    while (bignSum) {
        ans.num[ans.len++] = bignSum % 10;
        bignSum /= 10;
    }
 
    return ans;
}
 
bign bign::operator - (const int& b) {
    bign a = b;
    return *this - a;
}
 
 
bign bign::operator - (const bign& b) {
    ll bignSub = 0;
    bign ans;
    for (int i = 0; i < len || i < b.len; i++) {
        bignSub += num[i];
        if (i < b.len)
            bignSub -= b.num[i];
        ans.num[ans.len++] = (bignSub + 10) % 10;
        if (bignSub < 0) bignSub = -1;
        else bignSub = 0;
    }
    ans.DelZero();
    return ans;
}
 
bign bign::operator * (const ll& b) {
    ll bignSum = 0;
    bign ans;
 
    ans.len = len;
    for (int i = 0; i < len; i++) {
        bignSum += num[i] * b;
        ans.num[i] = bignSum % 10;
        bignSum /= 10;
    }
 
    while (bignSum) {
        ans.num[ans.len++] = bignSum % 10;
        bignSum /= 10;
    }
 
    return ans;
}
 
bign bign::operator * (const bign& b) {
    bign ans;
    ans.len = 0;
 
    for (int i = 0; i < len; i++){ 
        int bignSum = 0; 
 
        for (int j = 0; j < b.len; j++){ 
            bignSum += num[i] * b.num[j] + ans.num[i+j]; 
            ans.num[i+j] = bignSum % 10; 
            bignSum /= 10;
        } 
        ans.len = i + b.len; 
 
        while (bignSum){ 
            ans.num[ans.len++] = bignSum % 10; 
            bignSum /= 10;
        } 
    } 
    return ans;
}
 
bign bign::operator / (const ll& b) {
 
    bign ans;
 
    ll s = 0;
    for (int i = len-1; i >= 0; i--) {
        s = s * 10 + num[i];
        ans.num[i] = s/b;
        s %= b;
    }
 
    ans.len = len;
    ans.DelZero();
    return ans;
}
 
int bign::operator % (const int& b) {
 
    bign ans;
 
    int s = 0;
    for (int i = len-1; i >= 0; i--) {
        s = s * 10 + num[i];
        ans.num[i] = s/b;
        s %= b;
    }
 
    return s;
}

B:

#include <cstdio>
#include <cstring>
#include <queue>
#include <algorithm>
using namespace std;

const int MAXNODE = 205;
const int MAXEDGE = 210005;

typedef int Type;
const Type INF = 0x3f3f3f3f;

struct Edge {
	int u, v;
	Type cap, flow, low;
	Edge() {}
	Edge(int u, int v, Type cap, Type flow, Type low) {
		this->u = u;
		this->v = v;
		this->cap = cap;
		this->flow = flow;
		this->low = low;
	}
};

struct Dinic {
	int n, m, s, t;
	Edge edges[MAXEDGE];
	int first[MAXNODE];
	int next[MAXEDGE];
	bool vis[MAXNODE];
	Type d[MAXNODE];
	int cur[MAXNODE];
	vector<int> cut;

	void init(int n) {
		this->n = n;
		memset(first, -1, sizeof(first));
		m = 0;
	}
	void add_Edge(int u, int v, Type cap, Type low) {
		edges[m] = Edge(u, v, cap, 0, low);
		next[m] = first[u];
		first[u] = m++;
		edges[m] = Edge(v, u, 0, 0, low);
		next[m] = first[v];
		first[v] = m++;
	}

	bool bfs() {
		memset(vis, false, sizeof(vis));
		queue<int> Q;
		Q.push(s);
		d[s] = 0;
		vis[s] = true;
		while (!Q.empty()) {
			int u = Q.front(); Q.pop();
			for (int i = first[u]; i != -1; i = next[i]) {
				Edge& e = edges[i];
				if (!vis[e.v] && e.cap > e.flow) {
					vis[e.v] = true;
					d[e.v] = d[u] + 1;
					Q.push(e.v);
				}
			}
		}
		return vis[t];
	}

	Type dfs(int u, Type a) {
		if (u == t || a == 0) return a;
		Type flow = 0, f;
		for (int &i = cur[u]; i != -1; i = next[i]) {
			Edge& e = edges[i];
			if (d[u] + 1 == d[e.v] && (f = dfs(e.v, min(a, e.cap - e.flow))) > 0) {
				e.flow += f;
				edges[i^1].flow -= f;
				flow += f;
				a -= f;
				if (a == 0) break;
			}
		}
		return flow;
	}

	Type Maxflow(int s, int t) {
		this->s = s; this->t = t;
		Type flow = 0;
		while (bfs()) {
			for (int i = 0; i < n; i++)
				cur[i] = first[i];
			flow += dfs(s, INF);
		}
		return flow;
	}

	bool solve(int s, int t, int tot) {
		Maxflow(s, t); 
		for (int i = first[s]; i + 1; i = next[i]) {
			if (edges[i].flow != edges[i].cap) return false;
		}
		printf("YES
");
		for (int i = 0; i < 2 * tot; i += 2)
			printf("%d
", edges[i].flow + edges[i].low);
		return true;
	}

	void MinCut() {
		cut.clear();
		for (int i = 0; i < m; i += 2) {
			if (vis[edges[i].u] && !vis[edges[i].v])
				cut.push_back(i);
		}
	}
} gao;

const int N = 205;

int n, m, M[N];

int main() {
	while (~scanf("%d%d", &n, &m)) {
		gao.init(n + 2);
		int u, v, l, c;
		memset(M, 0, sizeof(M));
		for (int i = 0; i < m; i++) {
			scanf("%d%d%d%d", &u, &v, &l, &c);
			gao.add_Edge(u, v, c - l, l);
			M[u] -= l;
			M[v] += l;
		}
		for (int i = 1; i <= n; i++) {
			if (M[i] > 0) gao.add_Edge(0, i, M[i], 0);
			else if (M[i] < 0) gao.add_Edge(i, n + 1, -M[i], 0);
		}
		if (!gao.solve(0, n + 1, m)) printf("NO
");
	}
	return 0;
}

C:

#include <cstdio>
#include <cstring>
#include <queue>
#include <set>
#include <algorithm>
using namespace std;

const int N = 500005;

int n, fa[N], du[N], vis[N];
int out[N], on;

int main() {
	while (~scanf("%d", &n)) {
		int f;
		int ans = 0;
		memset(du, 0, sizeof(du));
		memset(vis, 0, sizeof(vis));
		for (int i = 2; i <= n; i++) {
			scanf("%d", &f);
			fa[i] = f;
			du[f]++;
		}
		on = 0;
		queue<int> Q;
		for (int i = 1; i <= n; i++) {
			if (du[i] == 0)
				Q.push(i);
		}
		while (!Q.empty()) {
			int u = Q.front();
			if (u == 1) break;
			Q.pop();
			if (!vis[u] && !vis[fa[u]]) {
				vis[fa[u]] = 1;
				out[on++] = u;
				ans += 1000;
			}
			du[fa[u]]--;
			if (du[fa[u]] == 0) Q.push(fa[u]);
		}
		sort(out, out + on);
		printf("%d
", ans);
		for (int i = 0; i < on; i++)
			printf("%d%c", out[i], i == on - 1 ? '
' : ' ');
	}
	return 0;
}

D:

#include <cstdio>
#include <cstring>

const int N = 10005;
const int M = 100005;

int n, m, cnt[N];
int u[M], v[M];

int main() {
	while (~scanf("%d%d", &n, &m)) {
		long long ans = 0;
		memset(cnt, 0, sizeof(cnt));
		for (int i = 0; i < m; i++) {
			scanf("%d%d", &u[i], &v[i]);
			cnt[u[i]]++;
			if (v[i] != u[i]) cnt[v[i]]++;
		}
		for (int i = 0; i < m; i++) {
			ans += cnt[u[i]];
			if (u[i] != v[i]) ans += cnt[v[i]];
		}
		printf("%lld
", ans);
	}
	return 0;
}

E:

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

typedef long long ll;
const ll MOD = 1000000000;
const int NUMLEN = 105;

struct Bign {
	ll num[NUMLEN];
	int len;

	void init(char *str) {
		for (int i = strlen(str) - 1; i >= 0; i--) {
			if (str[i] == '0') str[i] = '9';
			else {
				str[i]--;
				break;
			}
		}
		if (str[0] == '0') {
			int ca = strlen(str);
			for (int i = 0; i < ca; i++)
				str[i] = str[i + 1];
			str[ca - 1] = '';
		}
		len = 0;
		memset(num, 0, sizeof(num));
		for (int i = strlen(str) - 1; i >= 0; i -= 9) {
			for (int j = max(0, i - 8); j <= i; j++) {
				num[len] = num[len] * 10 + str[j] - '0';
			}
			len++;
		}
	}

	ll div2() {
		ll yu = 0;
		for (int i = len - 1; i >= 0; i--) {
			num[i] = num[i] + yu * MOD;
			yu = num[i] % 2;
			num[i] /= 2;
		}
		while (len > 1 && num[len - 1] == 0) len--;
		return yu;
	}
	
	bool iszero() {
		if (len == 1 && num[0] == 0) return true;
		return false;
	}

	void print() {
		for (int i = len - 1; i >= 0; i--) {
			if (i != len - 1) printf("%09lld", num[i]);
			else printf("%lld", num[i]);
		}
	}
} n;

const int N = 105;

char num[N];
int m, p, tot;

struct mat {
	int v[35][35];
	mat() {memset(v, 0, sizeof(v));}
	mat operator * (mat c) {
		mat ans;
		for (int k = 0; k < tot; k++) {
			for (int i = 0; i < tot; i++) {
				if (v[i][k] == 0) continue;
				for (int j = 0; j < tot; j++) {
					if (c.v[k][j] == 0) continue;
					ans.v[i][j] = (ans.v[i][j] + v[i][k] * c.v[k][j]) % p;
				}
			}
		}
		return ans;
	}
};

mat pow_mod(mat x, Bign k) {
	mat ans;
	for (int i = 0; i < tot; i++) ans.v[i][i] = 1;
	while (!k.iszero()) {
		ll sb = k.div2();
		if (sb == 1) ans = ans * x;
		x = x * x;
	}
	return ans;
}

int main() {
	while (~scanf("%s%d%d", num, &m, &p)) {
		n.init(num);
		tot = (1<<m);
		mat A;
		for (int i = 0; i < tot; i++) {
			for (int j = 0; j < tot; j++) {
				int flag = 1;
				int st = 3;
				for (int k = 0; k < m - 1; k++) {
					int sb = (i&st)>>k;
					if ((sb == 0 || sb == 3) && (i&st) == (j&st)) {
						flag = 0;
						break;
					}
					st <<= 1;
				}
				if (flag == 1) A.v[i][j] = 1;
			}
		}
		A = pow_mod(A, n);
		ll ans = 0;
		for (int i = 0; i < tot; i++) {
			for (int j = 0; j < tot; j++)
				ans = (ans + A.v[i][j]) % p;
		}
		printf("%lld
", ans);
	}
	return 0;
}

F:

#include <cstdio>
#include <cstring>
#include <vector>
#include <cmath>
#include <algorithm>
#include <queue>
using namespace std;

typedef double Type;

const double eps = 1e-6;
const int MAXNODE = 305;
const int MAXEDGE = 100005;

struct Edge {
	int u, v;
	Type dist;
	Edge() {}
	Edge(int u, int v, Type dist) {
		this->u = u;
		this->v = v;
		this->dist = dist;
	}
};

struct BellmanFrod {
	int n, m;
	Edge edges[MAXEDGE];
	int first[MAXNODE];
	int next[MAXEDGE];
	bool inq[MAXNODE];
	Type d[MAXNODE];
	int p[MAXNODE];
	int cnt[MAXNODE];

	void init(int n) {
		this->n = n;
		memset(first, -1, sizeof(first));
		m = 0;
	}

	void add_Edge(int u, int v, Type dist) {
		edges[m] = Edge(u, v, dist);
		next[m] = first[u];
		first[u] = m++;
	}

	bool negativeCycle() {
		queue<int> Q;
		memset(inq, 0, sizeof(inq));
		memset(cnt, 0, sizeof(cnt));
		for (int i = 0; i < n; i++) {
			d[i] = 0; inq[i] = true; Q.push(i);
		}

		while (!Q.empty()) {
			int u = Q.front();
			Q.pop();
			inq[u] = false;
			for (int i = first[u]; i != -1; i = next[i]) {
				Edge& e = edges[i];
				if (d[e.v] > eps + d[u] + e.dist) {
					d[e.v] = d[u] + e.dist;
					p[e.v] = i;
					if (!inq[e.v]) {
						Q.push(e.v);
						inq[e.v] = true;
						if (++cnt[e.v] > n) return true;
					}
				}
			}
		}
		return false;
	}
} gao;

const int N = 305;

int n;

struct Circle {
	double x, y, r;
	void read() {
		scanf("%lf%lf%lf", &x, &y, &r);
	}
} c[N], cc;

double dis(Circle a, Circle b) {
	double dx = a.x - b.x;
	double dy = a.y - b.y;
	return sqrt(dx * dx + dy * dy);
}

int main() {
	while (~scanf("%d", &n)) {
		for (int i = 0; i < n; i++) c[i].read();
		cc.read();
		for (int i = 0; i < n; i++) {
			c[i].x -= cc.x;
			c[i].y -= cc.y;
			c[i].r += cc.r;
		}
		cc.x = cc.y = 0;
		gao.init(n);
		for (int i = 0; i < n; i++) {
			for (int j = i + 1; j < n; j++) {
				if (c[i].r + c[j].r - eps < dis(c[i], c[j])) continue;
				double tmp = acos((c[i].x * c[j].x + c[i].y * c[j].y) / dis(c[i], cc) / dis(c[j], cc));
				bool flag = (c[i].x * c[j].y - c[i].y * c[j].x) >= 0;
				gao.add_Edge(i, j, flag ? tmp : -tmp);
				gao.add_Edge(j, i, flag ? -tmp : tmp);
			}
		}
		printf("%s
", !gao.negativeCycle() ? "YES" : "NO");
	}
	return 0;
}

G:

#include <cstdio>
#include <cstring>
#include <vector>
#include <algorithm>
using namespace std;

const int N = 100005;
int n;
struct Man {
	int a, b, id;
} man[N];

bool cmp(Man a, Man b) {
	if (a.a == b.a) return a.b > b.b;
	return a.a < b.a;
}

int dp[N], save[N], sn;

bool judge(Man a, Man b) {
	if (a.a <= b.a && a.b >= b.b) return false;
	if (a.a >= b.a && a.b <= b.b) return false;
	return true;
}

int main() {
	while (~scanf("%d", &n)) {
		for (int i = 1; i <= n; i++) {
			scanf("%d%d", &man[i].a, &man[i].b);
			man[i].id = i;
		}
		sort(man + 1, man + n + 1, cmp);
		memset(dp, 0, sizeof(dp));
		sn = 0;
		save[sn++] = 0;
		for (int i = 1; i <= n; i++) {
			int v = lower_bound(save, save + sn, man[i].b) - save;
			save[v] = man[i].b;
			if (v == sn) sn++;
			dp[i] = v;
		}
		int sum = sn - 1;
		printf("%d
", sum);
		int bo = 0;
		for (int i = n; i >= 1; i--) {
			if (dp[i] == sum) {
				if (bo) printf(" ");
				else bo = 1;
				printf("%d", man[i].id);
				sum--;
			}
		}
		printf("
");
	}
	return 0;
}

H:

#include <cstdio>
#include <cstring>
#include <iostream>

using namespace std;
typedef long long ll;
const int MAXN = 2005;

struct bign {
	int len;
	ll num[MAXN];

	bign () {
		len = 0;
		memset(num, 0, sizeof(num));
	}
	bign (ll number) {*this = number;}
	bign (const char* number) {*this = number;}

	void DelZero ();
	void Put ();

	void operator = (ll number);
	void operator = (char* number);

	bool operator <  (const bign& b) const;
	bool operator >  (const bign& b) const { return b < *this; }
	bool operator <= (const bign& b) const { return !(b < *this); }
	bool operator >= (const bign& b) const { return !(*this < b); }
	bool operator != (const bign& b) const { return b < *this || *this < b;}
	bool operator == (const bign& b) const { return !(b != *this); }

	void operator ++ ();
	void operator -- ();
	bign operator + (const int& b);
	bign operator + (const bign& b);
	bign operator - (const int& b);
	bign operator - (const bign& b);
	bign operator * (const ll& b);
	bign operator * (const bign& b);
	bign operator / (const ll& b);
	//bign operator / (const bign& b);
	int operator % (const int& b);
};

/*Code*/

int prime[10005], pn = 0, vis[10005];

void getprime() {
	for (int i = 2; i < 10000; i++) {
		if (vis[i]) continue;
		prime[pn++] = i;
		for (int j = i * i; j < 10000; j += i)
			vis[j] = 1;
	}
}

const int N = 105;
int m, n;
int A[N][N];

int gauss() {
	int i = 0, j = 0, k, r, u;
	while (i < m && j < n) {
		r = i;
		for (k = i; k < m; k++)
			if (A[k][j]) {r = k; break;}
		if (A[r][j]) {
			if (r != i) for (int k = 0; k <= n; k++) swap(A[r][k], A[i][k]);
			for (u = i + 1; u < m; u++) if (A[u][j])
				for (k = i; k <= n; k++) A[u][k] ^= A[i][k];
			i++;
		}
		j++;
	}
	return i;
}

int main() {
	getprime();
	while (~scanf("%d%d", &m, &n)) {
		memset(A, 0, sizeof(A));
		int num;
		for (int k = 0; k < n; k++) {
			scanf("%d", &num);
			for (int i = 0; i < m; i++) {
				if (num % prime[i] == 0) {
					int cnt = 0;
					while (num % prime[i] == 0) {
						num /= prime[i];
						cnt++;
					}
					if (cnt % 2) A[i][k] = 1;
				}
			}
		}
		int sb = gauss();
		bign ans = 1;
		for (int i = 0; i < n - sb; i++) {
			ans = ans + ans;
		}
		ans = ans - 1;
		ans.Put();
		printf("
");
	}
	return 0;
}



/*********************************************/

void bign::DelZero () {
	while (len && num[len-1] == 0)
		len--;

	if (len == 0) {
		num[len++] = 0;
	}
}

void bign::Put () {
	for (int i = len-1; i >= 0; i--) 
		printf("%lld", num[i]);
}

void bign::operator = (char* number) {
	len = strlen (number);
	for (int i = 0; i < len; i++)
		num[i] = number[len-i-1] - '0';
	DelZero ();
}

void bign::operator = (ll number) {

	len = 0;
	while (number) {
		num[len++] = number%10;
		number /= 10;
	}

	DelZero ();
}

bool bign::operator < (const bign& b) const {
	if (len != b.len)
		return len < b.len;
	for (int i = len-1; i >= 0; i--)
		if (num[i] != b.num[i])
			return num[i] < b.num[i];
	return false;
}

void bign::operator ++ () {
	int s = 1;

	for (int i = 0; i < len; i++) {
		s = s + num[i];
		num[i] = s % 10;
		s /= 10;
		if (!s) break;
	}

	while (s) {
		num[len++] = s%10;
		s /= 10;
	}
}

void bign::operator -- () {
	if (num[0] == 0 && len == 1) return;

	int s = -1;
	for (int i = 0; i < len; i++) {
		s = s + num[i];
		num[i] = (s + 10) % 10;
		if (s >= 0) break;
	}
	DelZero ();
}

bign bign::operator + (const int& b) {
	bign a = b;
	return *this + a;
}

bign bign::operator + (const bign& b) {
	int bignSum = 0;
	bign ans;

	for (int i = 0; i < len || i < b.len; i++) {
		if (i < len) bignSum += num[i];
		if (i < b.len) bignSum += b.num[i];

		ans.num[ans.len++] = bignSum % 10;
		bignSum /= 10;
	}

	while (bignSum) {
		ans.num[ans.len++] = bignSum % 10;
		bignSum /= 10;
	}

	return ans;
}

bign bign::operator - (const int& b) {
	bign a = b;
	return *this - a;
}


bign bign::operator - (const bign& b) {
	ll bignSub = 0;
	bign ans;
	for (int i = 0; i < len || i < b.len; i++) {
		bignSub += num[i];
		if (i < b.len)
			bignSub -= b.num[i];
		ans.num[ans.len++] = (bignSub + 10) % 10;
		if (bignSub < 0) bignSub = -1;
		else bignSub = 0;
	}
	ans.DelZero();
	return ans;
}

bign bign::operator * (const ll& b) {
	ll bignSum = 0;
	bign ans;

	ans.len = len;
	for (int i = 0; i < len; i++) {
		bignSum += num[i] * b;
		ans.num[i] = bignSum % 10;
		bignSum /= 10;
	}

	while (bignSum) {
		ans.num[ans.len++] = bignSum % 10;
		bignSum /= 10;
	}

	return ans;
}

bign bign::operator * (const bign& b) {
	bign ans;
	ans.len = 0; 

	for (int i = 0; i < len; i++){  
		int bignSum = 0;  

		for (int j = 0; j < b.len; j++){  
			bignSum += num[i] * b.num[j] + ans.num[i+j];  
			ans.num[i+j] = bignSum % 10;  
			bignSum /= 10;
		}  
		ans.len = i + b.len;  

		while (bignSum){  
			ans.num[ans.len++] = bignSum % 10;  
			bignSum /= 10;
		}  
	}  
	return ans;
}

bign bign::operator / (const ll& b) {

	bign ans;

	ll s = 0;
	for (int i = len-1; i >= 0; i--) {
		s = s * 10 + num[i];
		ans.num[i] = s/b;
		s %= b;
	}

	ans.len = len;
	ans.DelZero();
	return ans;
}

int bign::operator % (const int& b) {

	bign ans;

	int s = 0;
	for (int i = len-1; i >= 0; i--) {
		s = s * 10 + num[i];
		ans.num[i] = s/b;
		s %= b;
	}

	return s;
}