很傻的一场。
题目链接：https://atcoder.jp/contests/abc139/
A：
傻题。
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=1e5+10; 21 char s[maxn],t[maxn]; 22 23 int main() { 24 scanf("%s",s+1); 25 scanf("%s",t+1); 26 int ans=0; 27 for (int i=1;i<=3;i++) 28 ans+=s[i]==t[i]; 29 printf("%d\n",ans); 30 return 0; 31 }
B：
枚举就好了。
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 a, b; 21 22 int main() { 23 while (scanf("%d%d", &a, &b) != EOF) { 24 int curr=1,ans=0; 25 while (curr<b){ 26 curr+=a-1; 27 ans++; 28 } 29 printf("%d\n",ans); 30 } 31 return 0; 32 }
C：
倒着扫一次就好了。
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 = 1e5 + 10; 21 int n, a[maxn]; 22 23 int main() { 24 scanf("%d", &n); 25 for (int i = 1; i <= n; i++) scanf("%d", &a[i]); 26 int ans = 0, cnt = 0; 27 for (int i = n; i > 1; i--) { 28 if (a[i] <= a[i - 1]) cnt++; 29 else { 30 ans = max(ans, cnt); 31 cnt = 0; 32 } 33 } 34 ans = max(ans, cnt); 35 printf("%d\n", ans); 36 return 0; 37 }
D：
打个表就知道答案。
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 ll n; 21 22 int main() { 23 scanf("%lld", &n); 24 printf("%lld\n", (1ll + (n - 1)) * (n - 1) / 2); 25 return 0; 26 }
E：
队友说是模拟。(完全不想写
F：
n方暴力完事。
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; 21 vector<pair<ll, ll>> v; 22 23 int main() { 24 scanf("%d", &n); 25 for (int i = 1; i <= n; i++) { 26 pair<ll, ll> p; scanf("%lld%lld", &p.first, &p.second); 27 if (p.first || p.second) v.pb(p); 28 } 29 n = (int)v.size(); 30 sort(v.begin(), v.end(), [&](pair<ll, ll> a, pair<ll, ll> b) { 31 return atan2(a.second, a.first) < atan2(b.second, b.first); 32 }); 33 ll ans = 0; 34 for (int i = 0; i < n; i++) { 35 int j = i; ll x = 0, y = 0; 36 for (int k = 0; k < n; k++) { 37 x += v[j].first; y += v[j].second; 38 ans = max(ans, x * x + y * y); 39 if (++j == n) j = 0; 40 } 41 } 42 printf("%.15f\n", sqrt(ans)); 43 return 0; 44 }