Solution Set -「CF 1525」

「CF 1525A」Potion-making

Link.

显然。

#include<bits/stdc++.h>
typedef long long ll;
template<typename T>void sf(T &x){x=0;T f=0;char c=getchar();for(;c<'0'||c>'9';c=getchar())if(c=='-')f=1;for(;c>='0'&&c<='9';c=getchar())x=(x<<3)+(x<<1)+(c^'0');if(f)x=-x;}
template<typename T>void pf(T x,char l='
'){static T s[100],t;if(x<0)putchar('-'),x=-x;do s[++t]=x%10,x/=10;while(x);while(t)putchar(s[t--]^'0');putchar(l);}
int gcd(int x,int y){return !y?x:gcd(y,x%y);}
int main()
{
	int T,k;
	sf(T);
	while(T-->0)
	{
		sf(k);
		int p1=k,p2=100-k,x=gcd(p1,p2);
		p1/=x;
		p2/=x;
		pf(p1+p2);
	}
	return 0;
}

「CF 1525B」Permutation Sort

Link.

注意到答案只有 (0/1/2/3)，分类讨论即可。

吃了三发罚时

#include<bits/stdc++.h>
typedef long long ll;
template<typename T>void sf(T &x){x=0;T f=0;char c=getchar();for(;c<'0'||c>'9';c=getchar())if(c=='-')f=1;for(;c>='0'&&c<='9';c=getchar())x=(x<<3)+(x<<1)+(c^'0');if(f)x=-x;}
template<typename T>void pf(T x,char l='
'){static T s[100],t;if(x<0)putchar('-'),x=-x;do s[++t]=x%10,x/=10;while(x);while(t)putchar(s[t--]^'0');putchar(l);}
int T,n,a[60];
int main()
{
	for(sf(T);T;--T)
	{
		sf(n);
		for(int i=1;i<=n;++i)	sf(a[i]);
		int flag=1;
		for(int i=2;i<=n;++i)
		{
			if(a[i]!=a[i-1]+1)
			{
				flag=0;
				break;
			}
		}
		if(!flag)
		{
			if(a[1]==n && a[n]==1)	puts("3");
			else if(a[n]==n || a[1]==1)	puts("1");
			else	puts("2");
		}
		else	puts("0");
	}
	return 0;
}

「CF 1525C」Robot Collisions

Link.

显然我不会。

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define mp make_pair
template<typename T>void sf(T &x) {
    x = 0;
    T f = 0;
    char c = getchar();

    for (; c < '0' || c > '9'; c = getchar())
        if (c == '-')
            f = 1;

    for (; c >= '0' && c <= '9'; c = getchar())
        x = (x << 3) + (x << 1) + (c^'0');

    if (f)
        x = -x;
}
template<typename T>void pf(T x, char l = '
') {
    static T s[100], t;

    if (x < 0)
        putchar('-'), x = -x;

    do
        s[++t] = x % 10, x /= 10;

    while (x)
        ;

    while (t)
        putchar(s[t--]^'0');

    putchar(l);
}
struct st {
    int a, b, id;
} Sts[300005], Uji[300005], Qql[300005];
bool cmp(st A, st B) {
    return A.a < B.a;
}
int reait[300005];
int n, m;
int U(int x, int y) {
    int res = 0;

    if (Sts[x].a < Sts[y].a) {
        if (Sts[x].b == 0)
            res += Sts[x].a, Sts[x].a = 0;

        if (Sts[y].b == 1)
            res += (m - Sts[y].a), Sts[y].a = m;

        return (res + abs(Sts[x].a - Sts[y].a)) / 2;
    } else {
        if (Sts[x].b == 1)
            res += (m - Sts[x].a), Sts[x].a = m;

        if (Sts[y].b == 0)
            res += Sts[y].a, Sts[y].a = 0;

        return (res + abs(Sts[x].a - Sts[y].a)) / 2;
    }
}
signed main() {
    int T;
    sf(T);

    while (T--) {
        sf(n), sf(m);

        for (int i = 1; i <= n; i++)
            reait[i] = -1;

        int rks = 0, tss = 0;

        for (int i = 1; i <= n; i++) {
            sf(Sts[i].a);
            Sts[i].id = i;
        }

        for (int i = 1; i <= n; i++) {
            char res = getchar();

            while (res != 'L' && res != 'R')
                res = getchar();

            Sts[i].b = res == 'R';
        }

        for (int i = 1; i <= n; i++) {
            if (Sts[i].a & 1)
                Qql[++tss] = Sts[i];
            else
                Uji[++rks] = Sts[i];
        }

        sort(Uji + 1, Uji + rks + 1, cmp);
        sort(Qql + 1, Qql + tss + 1, cmp);
        stack <int> Q;
        Q.push(1);

        for (int i = 2; i <= rks; i++) {
            if (Uji[i].b == 0 && !Q.empty()) {
                int u = Q.top();
                Q.pop();
                reait[Uji[i].id] = reait[Uji[u].id] = U(Uji[i].id, Uji[u].id);
            } else
                Q.push(i);
        }

        while (!Q.empty()) {
            int u = Q.top();
            Q.pop();

            if (!Q.empty()) {
                int v = Q.top();
                Q.pop();
                reait[Uji[u].id] = reait[Uji[v].id] = U(Uji[u].id, Uji[v].id);
            }
        }

        Q.push(1);

        for (int i = 2; i <= tss; i++) {
            if (Qql[i].b == 0 && !Q.empty()) {
                int u = Q.top();
                Q.pop();
                reait[Qql[i].id] = reait[Qql[u].id] = U(Qql[i].id, Qql[u].id);
            } else
                Q.push(i);
        }

        while (!Q.empty()) {
            int u = Q.top();
            Q.pop();

            if (!Q.empty()) {
                int v = Q.top();
                Q.pop();
                reait[Qql[u].id] = reait[Qql[v].id] = U(Qql[u].id, Qql[v].id);
            }
        }

        for (int i = 1; i <= n; i++)
            printf("%lld ", reait[i]);

        printf("
");
    }

    return 0;
}

「CF 1525D」Armchairs

Link.

设 (f(i,j)) 表示考虑把第 (j) 个人放进前 (i) 个座位里的方案，转移。

多久没写 DP 了啊，这种水平的 DP 都写漏一堆东西。

#include<bits/stdc++.h>
typedef long long ll;
template<typename T>void sf(T &x){x=0;T f=0;char c=getchar();for(;c<'0'||c>'9';c=getchar())if(c=='-')f=1;for(;c>='0'&&c<='9';c=getchar())x=(x<<3)+(x<<1)+(c^'0');if(f)x=-x;}
template<typename T>void pf(T x,char l='
'){static T s[100],t;if(x<0)putchar('-'),x=-x;do s[++t]=x%10,x/=10;while(x);while(t)putchar(s[t--]^'0');putchar(l);}
int n,a[5010],fr[5010],t0,oc[5010],t1,op[5010];
ll dp[5010][5010],ans=std::numeric_limits<ll>::max();
inline int fs(int x){return x<0?-x:x;}
int main()
{
	sf(n);
	for(int i=1;i<=n;++i)
	{
		sf(a[i]);
		if(a[i])	oc[++t1]=i;
		else	fr[++t0]=i;
	}
	for(int i=1;i<=t1;++i)	for(int j=0;j<=n;++j)	dp[i][j]=1e18;
	for(int i=1;i<=t1;++i)	for(int j=1;j<=n;++j) {
		dp[i][j]=dp[i][j-1];
		if(!a[j])	dp[i][j]=std::min(dp[i][j],dp[i-1][j-1]+fs(oc[i]-j));
	}
	pf(dp[t1][n]);
	return 0;
}

「CF 1525E」Assimilation IV

Link.

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「CF 1525F」Goblins And Gnomes

Link.

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