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 ",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 ",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 ",ans); 57 return 0; 58 }
这场比赛没有好好做，因为看起来都是些sb题。。。