8.22 猿辅导
1. 逆时针输出完全二叉树边界,AC
#include <bits/stdc++.h>
using namespace std;
int n, m;
int a[1000005];
int main()
{
scanf("%d", &n);
for(int i = 0 ; i < n ; i++){
scanf("%d",&a[i]);
}
int id = 0;
vector<vector<int>> tree;
vector<vector<bool>> vis;
for(int i = 0 ; id < n ; i++){
vector<int> t;
vector<bool> v;
for(int j = 0 ; j < (1<<i) && id < n ; j++){
t.push_back(a[id++]);
v.push_back(0);
}
tree.push_back(t);
vis.push_back(v);
}
int h = tree.size();
vector<int> ans;
for(int i = 0 ; i < h ; i++){
if(vis[i][0]) continue;
vis[i][0] = true;
ans.push_back(tree[i][0]);
}
for(int i = 0 ; i < tree[h-1].size() ; i++){
if(vis[h-1][i]) continue;
vis[h-1][i] = true;
ans.push_back(tree[h-1][i]);
}
if(tree[h-1].size() != 1<<(h-1)){
for(int i = (tree[h-1].size() + 1)/2 ; i < tree[h-2].size() ; i++){
if(vis[h-2][i]) continue;
vis[h-2][i] = true;
ans.push_back(tree[h-2][i]);
}
}
for(int i = h-1; i > 0 ; i--){
int l = tree[i].size();
if(vis[i][l-1]) continue;
vis[i][l-1] = true;
ans.push_back(tree[i][l-1]);
}
for(int i = 0 ; i < ans.size() ; i++)
printf("%d%c", ans[i], i==ans.size()-1?'\n':' ');
return 0;
} 2. 最大矩形和,带滚动的。50%
#include <bits/stdc++.h>
using namespace std;
int n, m;
typedef long long ll ;
ll a[105][2005];
ll sum[105][2005];
ll res[2005];
ll f(){
ll mmax = res[0];
ll t[m];
memset(t, 0, sizeof(t));
t[0] = res[0];
for(int i = 1 ; i < m ; i++){
t[i] = res[i];
if(t[i-1] > 0)
t[i] += t[i-1];
mmax = max(mmax, t[i]);
}
return mmax;
}
int main()
{
scanf("%d %d", &n, &m);
for(int i = 0 ; i < n ; i++){
for(int j = 0 ; j < m ; j++){
scanf("%lld", &a[i][j]);
}
for(int j = m ; j < m+m ; j++){
a[i][j] = a[i][j-m];
}
}
m*=2;
for(int j = 0 ; j < m ; j++)
sum[0][j] = a[0][j];
for(int i = 1 ; i < n ; i++){
for(int j = 0 ; j < m ; j++){
sum[i][j] = sum[i-1][j] + a[i][j];
}
}
ll ans = a[0][0];
for(int i = 0 ; i < n ; i++){
for(int j = i ; j < n ; j++){
memset(res, 0, sizeof(res));
for(int k = 0 ; k < m ; k++){
if(i==0)
res[k] = sum[j][k];
else
res[k] = sum[j][k] - sum[i-1][k];
}
ll t = f();
ans = max(ans, t);
}
}
printf("%lld\n", ans);
return 0;
}