题目质量差评！为什么不给数据范围!
A.乘积最大3
题目：http://dev.luogu.org/problem/show?pid=2172
题解：sb题，均值定理。
代码：
1 #include<cstdio>
2 #include<cstdlib>
3 #include<cmath>
4 #include<cstring>
5 #include<algorithm>
6 #include<iostream>
7 #include<vector>
8 #include<map>
9 #include<set>
10 #include<queue>
11 #include<string>
12 #define inf 1000000000
13 #define maxn 10000000
14 #define maxm 500+100
15 #define eps 1e-10
16 #define ll long long
17 #define pa pair<int,int>
18 #define for0(i,n) for(int i=0;i<=(n);i++)
19 #define for1(i,n) for(int i=1;i<=(n);i++)
20 #define for2(i,x,y) for(int i=(x);i<=(y);i++)
21 #define for3(i,x,y) for(int i=(x);i>=(y);i--)
22 #define mod 1000000007
23 using namespace std;
24 inline ll read()
25 {
26 ll x=0,f=1;char ch=getchar();
27 while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
28 while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}
29 return x*f;
30 }
31 ll n,m,tmp,a[maxn];
32 int main()
33 {
34 freopen("input.txt","r",stdin);
35 freopen("output.txt","w",stdout);
36 n=read();m=read();
37 for1(i,m)a[i]=n/m;
38 tmp=n-(n/m)*m;
39 for3(i,m,m-tmp+1)a[i]++;
40 for1(i,m-1)printf("%lld ",a[i]);
41 printf("%lld\n",a[m]);
42 return 0;
43 }
B.刮油漆
题目：http://dev.luogu.org/problem/show?pid=U155
题解：先差分算出每个点的高度，然后单调栈搞掉。
不知道哪写残了一直WA，没AK真不爽。。。
代码：
1 #include<cstdio>
2 #include<cstdlib>
3 #include<cmath>
4 #include<cstring>
5 #include<algorithm>
6 #include<iostream>
7 #include<vector>
8 #include<map>
9 #include<set>
10 #include<queue>
11 #include<string>
12 #define inf 1000000000
13 #define maxn 1000000+1000
14 #define maxm 500+100
15 #define eps 1e-10
16 #define ll long long
17 #define pa pair<int,int>
18 #define for0(i,n) for(int i=0;i<=(n);i++)
19 #define for1(i,n) for(int i=1;i<=(n);i++)
20 #define for2(i,x,y) for(int i=(x);i<=(y);i++)
21 #define for3(i,x,y) for(int i=(x);i>=(y);i--)
22 #define mod 1000000007
23 using namespace std;
24 inline int read()
25 {
26 int x=0,f=1;char ch=getchar();
27 while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
28 while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}
29 return x*f;
30 }
31 int n,ans,mx,top,a[maxn],b[maxn],sta[maxn];
32 int main()
33 {
34 freopen("input.txt","r",stdin);
35 freopen("output.txt","w",stdout);
36 n=read();
37 for1(i,n)
38 {
39 int x=read(),y=read();
40 a[x]++,a[y+1]--;
41 if(y+1>mx)mx=y+1;
42 }
43 for1(i,mx)b[i]=b[i-1]+a[i];
44 ans=mx;
45 sta[top=1]=0;
46 for1(i,mx)
47 {
48 while(top>1&&sta[top]>b[i])top--;
49 if(sta[top]==b[i])ans--;else sta[++top]=b[i];
50 }
51 printf("%d\n",ans);
52 return 0;
53 }
C.选学霸
题目：http://dev.luogu.org/problem/show?pid=2170
题解：并查集完了之后背包，怎么昨天一天做了两道这种题？
代码：
1 #include<cstdio>
2 #include<cstdlib>
3 #include<cmath>
4 #include<cstring>
5 #include<algorithm>
6 #include<iostream>
7 #include<vector>
8 #include<map>
9 #include<set>
10 #include<queue>
11 #include<string>
12 #define inf 1000000000
13 #define maxn 1000000+1000
14 #define maxm 500+100
15 #define eps 1e-10
16 #define ll long long
17 #define pa pair<int,int>
18 #define for0(i,n) for(int i=0;i<=(n);i++)
19 #define for1(i,n) for(int i=1;i<=(n);i++)
20 #define for2(i,x,y) for(int i=(x);i<=(y);i++)
21 #define for3(i,x,y) for(int i=(x);i>=(y);i--)
22 #define mod 1000000007
23 using namespace std;
24 inline int read()
25 {
26 int x=0,f=1;char ch=getchar();
27 while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
28 while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}
29 return x*f;
30 }
31 int n,m,k,ans,tot,sum,fa[maxn],a[maxn],s[maxn];
32 bool f[maxn];
33 inline int find(int x){return fa[x]==x?x:fa[x]=find(fa[x]);}
34 int main()
35 {
36 freopen("input.txt","r",stdin);
37 freopen("output.txt","w",stdout);
38 n=read();k=read();m=read();
39 for1(i,n)fa[i]=i;
40 for1(i,m)
41 {
42 int x=find(read()),y=find(read());
43 if(x!=y)fa[x]=y;
44 }
45 for1(i,n)s[find(i)]++;
46 for1(i,n)if(s[i])a[++tot]=s[i];
47 f[0]=1;
48 for1(i,tot)
49 {
50 for3(j,sum,0)
51 if(f[j])f[j+a[i]]=1;
52 sum+=a[i];
53 }
54 for3(i,k,1)if(f[i]){ans=i;break;}
55 for2(i,k,n)if(f[i]){if(abs(i-k)<k-ans)ans=i;break;}
56 printf("%d\n",ans);
57 return 0;
58 }
这场比赛没有好好做，因为看起来都是些sb题。。。
时间： 2024-08-26 10:41:49