AtCoder Beginner Contest 237
A
#include <bits/stdc++.h>
#define int long long
using namespace std;
int T, n, m;
signed main() {
cin >> n;
int a = 2147483648;
int b = a * -1;
a --;
if (n >= b && n <= a) cout << "Yes" << endl;
else cout << "No" << endl;
return 0;
}
B
#include <bits/stdc++.h>
using namespace std;
int T, n, m;
int main() {
cin >> n >> m;
vector<vector<int>> a(n + 1, vector<int>(m + 1)), b(m + 1, vector<int>(n + 1));
for (int i = 1; i <= n; i ++ )
for (int j = 1; j <= m; j ++ )
cin >> a[i][j];
for (int i = 1; i <= m; i ++ )
for (int j = 1; j <= n; j ++ )
b[i][j] = a[j][i];
for (int i = 1; i <= m; i ++ ) {
for (int j = 1; j <= n; j ++ )
cout << b[i][j] << " ";
cout << endl;
}
return 0;
}
C
#include <bits/stdc++.h>
using namespace std;
char s[1000010];
int main() {
cin >> s + 1;
int n = strlen(s + 1);
int pos = strlen(s + 1);
int start = 1;
while (start <= n && s[start] == 'a') start ++;
while (pos && s[pos] == 'a') pos --;
bool flag = 1;
int len1 = start - 1, len2 = n - pos;
while (start < pos) {
if (s[start] != s[pos]) {
flag = 0;
break;
}
start ++, pos --;
}
if (flag && len2 >= len1) cout << "Yes" << endl;
else cout << "No" << endl;
return 0;
}
D
#include <bits/stdc++.h>
using namespace std;
int T, n, m;
char s[500010];
int main() {
cin >> n;
cin >> s + 1;
deque<int> q;
q.push_back(n);
for (int i = n; i >= 1; i -- ) {
if (s[i] == 'L')
q.push_back(i - 1);
else
q.push_front(i - 1);
}
for (int i = 0; i < q.size(); i ++ )
cout << q[i] << " ";
cout << endl;
return 0;
}
E
spfa跑最长路
#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10, M = N * 2;
int n, m, res;
int g[N], dist[N];
bool st[N];
int h[N], e[M], ne[M], w[M], idx;
void add(int a, int b, int c)
{
e[idx] = b, ne[idx] = h[a], w[idx] = c, h[a] = idx ++;
}
void spfa()
{
memset(dist, 0xcf, sizeof dist);
dist[1] = 0;
queue<int> q;
q.push(1);
st[1] = true;
while (q.size())
{
auto t = q.front();
q.pop();
st[t] = false;
for (int i = h[t]; i != -1; i = ne[i])
{
int j = e[i];
if (dist[j] < dist[t] + w[i])
{
dist[j] = dist[t] + w[i];
if (!st[j])
{
q.push(j);
st[j] = true;
}
}
}
}
}
int main() {
memset(h, -1, sizeof h);
cin >> n >> m;
for (int i = 1; i <= n; i ++ ) cin >> g[i];
while (m -- ) {
int a, b;
cin >> a >> b;
if (g[a] > g[b]) {add(a, b, g[a] - g[b]); add(b, a, 2 * (g[b] - g[a]));}
else if (g[a] < g[b]) {add(a, b, 2 * (g[a] - g[b])); add(b, a, g[b] - g[a]);}
else {add(a, b, 0); add(b, a, 0);}
}
spfa();
for (int i = 1; i <= n; i ++ ) {
if (dist[i] == 0xcfcfcfcf) dist[i] = -1;
res = max(res, dist[i]);
}
cout << res << endl;
return 0;
}