【AtCoder】Yahoo Programming Contest 2019

A - Anti-Adjacency

K <= (N + 1) / 2

#include <bits/stdc++.h>
#define fi first
#define se second
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define space putchar(' ')
#define enter putchar('\n')
#define MAXN 40005
#define eps 1e-12
//#define ivorysi
using namespace std;
typedef long long int64;
typedef unsigned int u32;
typedef double db;
template<class T>
void read(T &res) {
	res = 0;T f = 1;char c = getchar();
	while(c < '0' || c > '9') {
		if(c == '-') f = -1;
		c = getchar();
	}
	while(c >= '0' && c <= '9') {
		res = res * 10 + c - '0';
		c = getchar();
	}
	res *= f;
}
template<class T>
void out(T x) {
	if(x < 0) {x = -x;putchar('-');}
	if(x >= 10) {
		out(x / 10);
	}
	putchar('0' + x % 10);
}
int N,K;
int main() {
#ifdef ivorysi
	freopen("f1.in","r",stdin);
#endif
	read(N);read(K);
	if(K <= (N + 1) / 2) puts("YES");
	else puts("NO");
}

B - Path

点度都不超过3

#include <bits/stdc++.h>
#define fi first
#define se second
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define space putchar(' ')
#define enter putchar('\n')
#define MAXN 40005
#define eps 1e-12
//#define ivorysi
using namespace std;
typedef long long int64;
typedef unsigned int u32;
typedef double db;
template<class T>
void read(T &res) {
	res = 0;T f = 1;char c = getchar();
	while(c < '0' || c > '9') {
		if(c == '-') f = -1;
		c = getchar();
	}
	while(c >= '0' && c <= '9') {
		res = res * 10 + c - '0';
		c = getchar();
	}
	res *= f;
}
template<class T>
void out(T x) {
	if(x < 0) {x = -x;putchar('-');}
	if(x >= 10) {
		out(x / 10);
	}
	putchar('0' + x % 10);
}
int deg[5];
int main() {
#ifdef ivorysi
	freopen("f1.in","r",stdin);
#endif
	int a,b;
	for(int i = 1 ; i <= 3 ; ++i) {
		read(a);read(b);
		++deg[a];++deg[b];
	}
	for(int i = 1 ; i <= 4 ; ++i) {
		if(deg[i] >= 3) {puts("NO");return 0;}
	}
	puts("YES");
}

C - When I hit my pocket...

先给自己加到A块饼干

然后判断一下B - A是否大于2，然后就用两次不断的换B - A

否则就直接一直拍得一次饼干就行

#include <bits/stdc++.h>
#define fi first
#define se second
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define space putchar(' ')
#define enter putchar('\n')
#define MAXN 40005
#define eps 1e-12
//#define ivorysi
using namespace std;
typedef long long int64;
typedef unsigned int u32;
typedef double db;
template<class T>
void read(T &res) {
	res = 0;T f = 1;char c = getchar();
	while(c < '0' || c > '9') {
		if(c == '-') f = -1;
		c = getchar();
	}
	while(c >= '0' && c <= '9') {
		res = res * 10 + c - '0';
		c = getchar();
	}
	res *= f;
}
template<class T>
void out(T x) {
	if(x < 0) {x = -x;putchar('-');}
	if(x >= 10) {
		out(x / 10);
	}
	putchar('0' + x % 10);
}
int64 K,A,B;
int main() {
#ifdef ivorysi
	freopen("f1.in","r",stdin);
#endif
	read(K);read(A);read(B);
	int64 now = 1;
	if(now < A) {
		int64 t = min(A - now,K);
		now += t;
		K -= t;
	}
	if(B - A > 2) {
		now += K / 2 * (B - A);
		K %= 2;
	}
	now += K;
	out(now);enter;
}

D - Ears

DEF我做题顺序是反的，D题我做的有点智障

FE做完之后一开榜19，D做完掉到45

大家AK水平那么高= =

事实上就是一个有点智障的dp

空 偶 奇 偶 空

每个段都可以为0，如果一个数在空段代价是它的值，奇数在偶段代价为1，偶数在奇数段代价为1，0在偶数段代价为2

#include <bits/stdc++.h>
#define fi first
#define se second
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define space putchar(' ')
#define enter putchar('\n')
#define MAXN 200005
#define eps 1e-12
//#define ivorysi
using namespace std;
typedef long long int64;
typedef unsigned int u32;
typedef double db;
template<class T>
void read(T &res) {
	res = 0;T f = 1;char c = getchar();
	while(c < '0' || c > '9') {
		if(c == '-') f = -1;
		c = getchar();
	}
	while(c >= '0' && c <= '9') {
		res = res * 10 + c - '0';
		c = getchar();
	}
	res *= f;
}
template<class T>
void out(T x) {
	if(x < 0) {x = -x;putchar('-');}
	if(x >= 10) {
		out(x / 10);
	}
	putchar('0' + x % 10);
}
int L;
int64 dp[MAXN][6],A[MAXN];
void Solve() {
	read(L);
	for(int i = 1 ; i <= L ; ++i) {read(A[i]);}
	for(int i = 1 ; i <= 4 ; ++i) dp[0][i] = 1e16;
	dp[0][0] = 0;
	for(int i = 1 ; i <= L ; ++i) {
		dp[i][0] = dp[i - 1][0] + A[i];
		int t = A[i] & 1;
		dp[i][1] = min(dp[i - 1][1],dp[i - 1][0]);

		dp[i][2] = min(min(dp[i - 1][1],dp[i - 1][0]),dp[i - 1][2]);
		if(A[i] % 2 == 0) dp[i][2]++;
		dp[i][3] = min(dp[i - 1][2],dp[i - 1][3]);
		if(A[i] & 1) {dp[i][1]++;dp[i][3]++;}
		if(A[i] == 0) {dp[i][1] += 2;dp[i][3] += 2;}
		dp[i][4] = min(min(dp[i - 1][3],dp[i - 1][2]),min(dp[i - 1][1],dp[i - 1][4]));
		dp[i][4] += A[i];
	}
	int64 res = dp[L][0];
	for(int i = 1 ; i <= 4 ; ++i) res = min(res,dp[L][i]);
	out(res);enter;
}
int main() {
#ifdef ivorysi
	freopen("f1.in","r",stdin);
#endif
	Solve();
}

E - Odd Subrectangles

如果选的行数确定了，那么选某一列的奇偶性也会确定，如果奇数有a列，偶数有b列，\(a + b = M\)

那么方案数是选a中奇数个，b随便选

方案数是\(2^{a - 1}\cdot 2^{b}\)，发现这个就是\(2^{M - 1}\)

所以只要存在a即可，即选的行数的数异或起来值不为0，转而求异或为0的方案，直接上线性基即可

#include <bits/stdc++.h>
#define fi first
#define se second
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define space putchar(' ')
#define enter putchar('\n')
#define MAXN 40005
#define eps 1e-12
//#define ivorysi
using namespace std;
typedef long long int64;
typedef unsigned int u32;
typedef double db;
template<class T>
void read(T &res) {
	res = 0;T f = 1;char c = getchar();
	while(c < '0' || c > '9') {
		if(c == '-') f = -1;
		c = getchar();
	}
	while(c >= '0' && c <= '9') {
		res = res * 10 + c - '0';
		c = getchar();
	}
	res *= f;
}
template<class T>
void out(T x) {
	if(x < 0) {x = -x;putchar('-');}
	if(x >= 10) {
		out(x / 10);
	}
	putchar('0' + x % 10);
}
const int MOD = 998244353;
int N,M;
int a[305][305];
int b[305][305],cnt;
int inc(int a,int b) {
	return a + b >= MOD ? a + b - MOD : a + b;
}
int mul(int a,int b) {
	return 1LL * a * b % MOD;
}
void update(int &x,int y) {
	x = inc(x,y);
}
int fpow(int x,int c) {
	int res = 1,t = x;
	while(c) {
		if(c & 1) res = mul(res,t);
		t = mul(t,t);
		c >>= 1;
	}
	return res;
}
void Solve() {
	read(N);read(M);
	for(int i = 1 ; i <= N ; ++i) {
		for(int j = 1 ; j <= M ; ++j) {
			read(a[i][j]);
		}
	}
	for(int i = 1 ; i <= N ; ++i) {
		for(int j = 1 ; j <= M ; ++j) {
			if(a[i][j]) {
				if(!b[j][j]) {
					for(int k = 1 ; k <= M ; ++k) b[j][k] = a[i][k];
					++cnt;
					break;
				}
				else {
					for(int k = 1 ; k <= M ; ++k) a[i][k] ^= b[j][k];
				}
			}
		}
	}
	int ans = inc(fpow(2,N),MOD - fpow(2,N - cnt));
	ans = mul(ans,fpow(2,M - 1));
	out(ans);enter;
}
int main() {
#ifdef ivorysi
	freopen("f1.in","r",stdin);
#endif
	Solve();
}

F - Pass

直接转二维平面，然后第i步能走到的点\((a,b)\)a个红球，b个蓝球，要满足a小于等于前i个人红球总和，b小于等于前i个人蓝球总和

#include <bits/stdc++.h>
#define fi first
#define se second
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define space putchar(' ')
#define enter putchar('\n')
#define MAXN 40005
#define eps 1e-12
//#define ivorysi
using namespace std;
typedef long long int64;
typedef unsigned int u32;
typedef double db;
template<class T>
void read(T &res) {
	res = 0;T f = 1;char c = getchar();
	while(c < '0' || c > '9') {
		if(c == '-') f = -1;
		c = getchar();
	}
	while(c >= '0' && c <= '9') {
		res = res * 10 + c - '0';
		c = getchar();
	}
	res *= f;
}
template<class T>
void out(T x) {
	if(x < 0) {x = -x;putchar('-');}
	if(x >= 10) {
		out(x / 10);
	}
	putchar('0' + x % 10);
}
const int MOD = 998244353;
char s[2005];
int sum[2005][2],N;
int dp[4005][4005];
int inc(int a,int b) {
	return a + b >= MOD ? a + b - MOD : a + b;
}
int mul(int a,int b) {
	return 1LL * a * b % MOD;
}
void update(int &x,int y) {
	x = inc(x,y);
}
void Solve() {
	scanf("%s",s + 1);
	N = strlen(s + 1);
	for(int i = 1 ; i <= N ; ++i) {
		sum[i][0] = sum[i - 1][0];
		sum[i][1] = sum[i - 1][1];
		if(s[i] == '0') sum[i][0] += 2;
		if(s[i] == '1') {sum[i][0]++;sum[i][1]++;}
		if(s[i] == '2') sum[i][1] += 2;
	}
	dp[0][0] = 1;
	for(int i = 1 ; i <= 2 * N ; ++i) {
		int t = min(i,N);
		for(int j = 0 ; j <= i ; ++j) {
			int a = j,b = i - j;
			if(a <= sum[t][0] && b <= sum[t][1]) {
				if(a) update(dp[a][b],dp[a - 1][b]);
				if(b) update(dp[a][b],dp[a][b - 1]);
			}
		}
	}
	out(dp[sum[N][0]][sum[N][1]]);enter;
}
int main() {
#ifdef ivorysi
	freopen("f1.in","r",stdin);
#endif
	Solve();
}