Large number of problems, usually in Java

e.g.

HDU1002

import Java.math.biginteger;import Java.util.Scanner; Public classMain { Public Static voidMain (string[] args) {Scanner cin=NewScanner (System.inch); intt=Cin.nextint ();        Cin.nextline (); intCnt=0;  while(t!=0) {T--; String S1=Cin.next (); String S2=Cin.next (); BigInteger A1=NewBigInteger (S1); BigInteger A2=NewBigInteger (S2); System. out. println (" Case"+ (++CNT) +":"); System. out. Print (a1+" + "+a2+" = "); System. out. println (A1.add (A2)); if(t!=0) System. out. println (); }            }}

HDU1715 Large Fibonacci number

ImportJava.math.BigInteger;ImportJava.util.Scanner; Public classMain {Private Staticbiginteger[] fib;  Public Static voidf () {fib=Newbiginteger[1005]; fib[2]=NewBigInteger ("1"); fib[1]=fib[2];  for(inti=3;i<1005;i++) {Fib[i]=fib[i-1].add (fib[i-2]); }    }     Public Static voidMain (string[] args) {Scanner cin=NewScanner (system.in); intt=Cin.nextint ();        Cin.nextline (); intCnt=0;        f ();  while(t!=0) {T--; CNT=Cin.nextint ();        System.out.println (fib[cnt]); }            }}

HDU1865

Analysis (RPM):

simple recursion + large number.
F[n]=f[n-1]+f[n-2].

Why?
since the numbers are only ' 1 ' and ' 2 ', then when you let Nth
When the bit is 1, f[n] plus f[n-1]; When you let the last two bits
Merged into 2, F[n] plus f[n-2] (because to ensure
The penultimate digit must be 1).

The calculated F is a Fibonacci sequence.

WOW, problem transformation is extremely ingenious.

The serious point of this recursive relationship is dynamic planning.

ImportJava.math.BigInteger;ImportJava.util.Scanner; Public classMain {Private Staticbiginteger[] fib;  Public Static voidf () {fib=Newbiginteger[1005]; fib[1]=NewBigInteger ("1"); fib[0]=fib[1];  for(inti=2;i<1005;i++) {Fib[i]=fib[i-1].add (fib[i-2]); }    }     Public Static voidMain (string[] args) {Scanner cin=NewScanner (system.in); intt=Cin.nextint ();        Cin.nextline (); intCnt=0;        f ();  while(t!=0) {T--; String s=Cin.next (); CNT=s.length ();        System.out.println (fib[cnt]); }            }}

Large number of problems, usually in Java