Codeforces Round #577 (Div. 2)

手速场。

A：

按题意模拟就完事了。

 1 /* basic header */
 2 #include <bits/stdc++.h>
 3 /* define */
 4 #define ll long long
 5 #define dou double
 6 #define pb emplace_back
 7 #define mp make_pair
 8 #define sot(a,b) sort(a+1,a+1+b)
 9 #define rep1(i,a,b) for(int i=a;i<=b;++i)
10 #define rep0(i,a,b) for(int i=a;i<b;++i)
11 #define eps 1e-8
12 #define int_inf 0x3f3f3f3f
13 #define ll_inf 0x7f7f7f7f7f7f7f7f
14 #define lson (curpos<<1)
15 #define rson (curpos<<1|1)
16 /* namespace */
17 using namespace std;
18 /* header end */
19 
20 int n, m;
21 string s[1010];
22 int a[1010];
23 ll ans = 0;
24 
25 int main() {
26     cin >> n >> m;
27     for (int i = 1; i <= n; i++) cin >> s[i];
28     for (int i = 1; i <= m; i++) cin >> a[i];
29     for (int j = 0; j < m; j++) {
30         int maxx = 0; map<char, int>m;
31         for (int i = 1; i <= n; i++) maxx = max(maxx, ++m[s[i][j]]);
32         ans += (ll)maxx * a[j + 1];
33     }
34     printf("%lld
", ans);
35     return 0;
36 }

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B：

检查所有元素的和是否为奇数，若为奇数则NO。

若最大元素大于和的一半，也为NO。

 1 /* basic header */
 2 #include <bits/stdc++.h>
 3 /* define */
 4 #define ll long long
 5 #define dou double
 6 #define pb emplace_back
 7 #define mp make_pair
 8 #define sot(a,b) sort(a+1,a+1+b)
 9 #define rep1(i,a,b) for(int i=a;i<=b;++i)
10 #define rep0(i,a,b) for(int i=a;i<b;++i)
11 #define eps 1e-8
12 #define int_inf 0x3f3f3f3f
13 #define ll_inf 0x7f7f7f7f7f7f7f7f
14 #define lson (curpos<<1)
15 #define rson (curpos<<1|1)
16 /* namespace */
17 using namespace std;
18 /* header end */
19 
20 int x, n, maxx = 0;
21 ll sum = 0;
22 
23 int main() {
24     scanf("%d", &n);
25     rep1(i, 1, n) {
26         int x; scanf("%d", &x);
27         maxx = max(maxx, x);
28         sum += x;
29     }
30     if (sum < maxx * 2 || sum & 1) puts("NO");
31     else puts("YES");
32     return 0;
33 }

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C：

直接从n/2+1这个位置往后填就可以了。

 1 /* basic header */
 2 #include <bits/stdc++.h>
 3 /* define */
 4 #define ll long long
 5 #define dou double
 6 #define pb emplace_back
 7 #define mp make_pair
 8 #define sot(a,b) sort(a+1,a+1+b)
 9 #define rep1(i,a,b) for(int i=a;i<=b;++i)
10 #define rep0(i,a,b) for(int i=a;i<b;++i)
11 #define eps 1e-8
12 #define int_inf 0x3f3f3f3f
13 #define ll_inf 0x7f7f7f7f7f7f7f7f
14 #define lson (curpos<<1)
15 #define rson (curpos<<1|1)
16 /* namespace */
17 using namespace std;
18 /* header end */
19 
20 const int maxn = 2e5 + 10;
21 ll n, k, a[maxn];
22 
23 int main() {
24     scanf("%lld%lld", &n, &k);
25     rep1(i, 1, n) scanf("%lld", &a[i]);
26     sot(a, n);
27     int cnt = 1;
28     for (int i = n / 2 + 1; i < n; i++) {
29         if (k / cnt >= a[i + 1] - a[i]) {
30             k -= (a[i + 1] - a[i]) * cnt;
31             cnt++;
32         } else return printf("%lld
", a[i] + k / cnt), 0;
33     }
34     printf("%lld
", a[n] + k / (n / 2 + 1));
35     return 0;
36 }

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