「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='\n'){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='\n'){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 = '\n') {
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("\n");
}
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='\n'){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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