Problem Link : https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=24&page=show_problem&problem=2661
Solution Idea:
In this problem the number of warriors is given and we have to say how many row can be made with them in this rule that the row contains warriors equal to row number (i th row contains i warriors). so that if there is 3 row there we have 1+2+3 = 6 worriers.
We can use binary search to solve this problem. let low=0 and high= 10000000000 (A large value ) and binary search the ans which satisfy the formula n*(n+1)/2 according to given input.
/* If opportunity doesn't knock, build a door. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S|.|S|.|R|.|A|.|S|.|A|.|M|.|K| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Success is how high you bounce when you hit bottom. */ #include <bits/stdc++.h> #define pii pair <int,int> #define pll pair <long long,long long> #define sc scanf #define pf printf #define Pi 2*acos(0.0) #define ms(a,b) memset(a, b, sizeof(a)) #define pb(a) push_back(a) #define MP make_pair #define db double #define ll long long #define EPS 10E-10 #define ff first #define ss second #define sqr(x) (x)*(x) #define D(x) cout<<#x " = "<<(x)<<endl #define VI vector <int> #define DBG pf("Hi\n") #define MOD 1000000007 #define CIN ios_base::sync_with_stdio(0); cin.tie(0) #define SZ(a) (int)a.size() #define sf(a) scanf("%d",&a) #define sfl(a) scanf("%lld",&a) #define sff(a,b) scanf("%d %d",&a,&b) #define sffl(a,b) scanf("%lld %lld",&a,&b) #define sfff(a,b,c) scanf("%d %d %d",&a,&b,&c) #define sfffl(a,b,c) scanf("%lld %lld %lld",&a,&b,&c) #define stlloop(v) for(__typeof(v.begin()) it=v.begin();it!=v.end();it++) #define loop(i,n) for(int i=0;i<n;i++) #define REP(i,a,b) for(int i=a;i<b;i++) #define RREP(i,a,b) for(int i=a;i>=b;i--) #define TEST_CASE(t) for(int z=1;z<=t;z++) #define PRINT_CASE printf("Case %d: ",z) #define CASE_PRINT cout<<"Case "<<z<<": " #define all(a) a.begin(),a.end() #define intlim 2147483648 #define infinity (1<<28) #define ull unsigned long long #define gcd(a, b) __gcd(a, b) #define lcm(a, b) ((a)*((b)/gcd(a,b))) using namespace std; /*----------------------Graph Moves----------------*/ //const int fx[]={+1,-1,+0,+0}; //const int fy[]={+0,+0,+1,-1}; //const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1}; // Kings Move //const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1}; // Kings Move //const int fx[]={-2, -2, -1, -1, 1, 1, 2, 2}; // Knights Move //const int fy[]={-1, 1, -2, 2, -2, 2, -1, 1}; // Knights Move /*------------------------------------------------*/ /*-----------------------Bitmask------------------*/ //int Set(int N,int pos){return N=N | (1<<pos);} //int reset(int N,int pos){return N= N & ~(1<<pos);} //bool check(int N,int pos){return (bool)(N & (1<<pos));} /*------------------------------------------------*/ ll ask(ll n) { return n*(n+1)/2; } int main() { // freopen("in.txt","r",stdin); ///freopen("out.txt","w",stdout); int t; cin>>t; TEST_CASE(t) { ll x; cin>>x; ll lo=0,hi=10000000000,ans=0; while(lo<=hi) { ll mid=(lo+hi)/2; ll temp=ask(mid); if(temp<=x) { ans=mid; lo=mid+1; } else hi=mid-1; } cout<<ans<<endl; } return 0; }