Codeforces Round #515 (Div. 3) （A、B、C、D、E）

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A

#include<bits/stdc++.h>
using namespace std;
#define clr(a) memset(a,0,sizeof(a))
#define line cout<<"-------------"<<endl

typedef long long ll;
const int maxn = 1e5 + 10;
const int MAXN = 1e6 + 10;
const int MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const int N = 1010;


int main(){
    ll t, l, v, r, L;
    scanf("%lld" ,&t);
    while(t--){
        scanf("%lld%lld%lld%lld", &L, &v, &l, &r);
        int num = L / v;
        int cnt = (l - 1) / v;
        int tem = r / v;
        cout << num + cnt - tem<< endl;
    }
    return 0;
}

B

#include<bits/stdc++.h>
using namespace std;
#define clr(a) memset(a, 0, sizeof(a))

const int N = 10100;
const int INF = 0x3f3f3f3f;

bool vis[N];
int a[N];

int main(){
    int n, r;
    while(scanf("%d%d", &n, &r) != EOF){
        clr(a); clr(vis);
        for(int i=1; i<=n; i++) scanf("%d", &a[i]);
        bool flag = true;
        int cnt = 0;
        int dis = 2 * (r - 1) + 1;
        int pos = INF;
        for(int i=1; i<=n; i++){
            if(a[i]){
                pos = i; break;
            }
        }
        if(pos > r) flag = false;
        else pos = r;
        n += (r - 1);
        while(pos <= n && pos > 0){
            if(a[pos]){
                if(vis[pos]){
                    flag = false; break;
                }
                else{
                   cnt++;
                   vis[pos] = true;
                }
            }
            else{
                while(!a[pos]) pos --;
                if(vis[pos]){
                    flag = false; break;
                }
                else{
                    cnt++;
                    vis[pos] = true;
                }
            }
            pos += dis;
        }
        if(!flag) puts("-1");
        else cout << cnt << endl;
    }
    return 0;
}

C

#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
const int maxn= 2e5 + 10;

int x[maxn], y[maxn];
char s[11];
int main(){
    int t ;
    cin >> t;
    int l = 0, r = 0;
    while (t --){
        scanf("%s", s);
        int id;
        scanf("%d", &id);
        if(s[0] == 'L'){
            l ++;
            x[id] = l;
        }
        else if(s[0] == 'R'){
            r ++;
            y[id] = r;
        }
        else if(s[0] == '?'){
            int ans;
            if (x[id] != 0)  ans = min(l-x[id], x[id]-1+r);
            else ans = min(r-y[id], y[id]-1+l);
            printf("%d\n", ans);
        }
    }
    return 0;
}

D

#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
const int maxn= 2e5 + 10;

ll a[maxn];
int main(){
    ll n, m, k;
    cin >> n >> m >> k;
    for (int i=n; i>=1; i--) scanf("%lld", &a[i]);
    ll temp = 0;
    ll ans = 0 , num = 0;
    for (int i=1; i<=n; i++){
        if (a[i] > k)  break;
        temp += a[i];
        if (temp > k){
            num ++;
            temp = a[i];
            if (num == m)  break;
        }
        ans ++;
    }
    printf("%lld\n", ans);
    return 0;
}

E

#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
const int maxn = 2e5 + 10;
const int MOD = 998244353;

char a[maxn], b[maxn];
string aa, bb;
vector<int> z(maxn);
#include<string.h>
int main() {
	int n, m, ans = 0;
	cin >> n >> m >> aa >> bb;
	reverse(aa.begin(), aa.end());
	reverse(bb.begin(), bb.end());
	strcpy(a, aa.c_str());
	strcpy(b, bb.c_str());
	int N = max(n, m), s = 1;
	for(int i=0; i<N; i++){
		z[i] = a[i] == '1' ? s : 0;
		z[i] = (z[i] + (i > 0 ? z[i - 1] : 0)) % MOD;
		s <<= 1;
		s %= MOD;
	}
	for(int i=0; i<m; i++){
		ans += b[i] == '1' ? z[i] : 0;
		ans %= MOD;
	}
	cout << ans << endl;
	return 0;
}