You are given a sequence [a1,โฆ,an][๐1,โฆ,๐๐] where each element ai๐๐ is either 00 or 11. You can apply several (possibly zero) operations to the sequence. In each operation, you select two integers 1โคlโคrโค|a|1โค๐โค๐โค|๐| (where |a||๐| is the current length of a๐) and replace [al,โฆ,ar][๐๐,โฆ,๐๐] with a single element x๐ฅ, where x๐ฅ is the majority of [al,โฆ,ar][๐๐,โฆ,๐๐].Here, the majority of a sequence consisting of 00 and 11 is defined as follows: suppose there are c0๐0 zeros and c1๐1 ones in the sequence, respectively.If c0โฅc1๐0โฅ๐1, the majority is 00.If c0<c1๐0<๐1, the majority is 11.For example, suppose a=[1,0,0,0,1,1]๐=[1,0,0,0,1,1]. If we select l=1,r=2๐=1,๐=2, the resulting sequence will be [0,0,0,1,1][0,0,0,1,1]. If we select l=4,r=6๐=4,๐=6, the resulting sequence will be [1,0,0,1][1,0,0,1].Determine if you can make a=[1]๐=[1] with a finite number of operations.InputEach test contains multiple test cases. The first line contains the number of test cases t๐ก (1โคtโค4โ 1041โค๐กโค4โ 104). Description of the test cases follows.The first line of each testcase contains one integer n๐ (1โคnโค2โ 1051โค๐โค2โ 105).The second line of each testcase contains a string consisting of 00 and 11, describing the sequence a๐.It's guaranteed that the sum of n๐ over all testcases does not exceed 2โ 1052โ 105.OutputFor each testcase, if it's possible to make a=[1]๐=[1], print YES. Otherwise, print NO. You can output the answer in any case (upper or lower). For example, the strings yEs, yes, Yes, and YES will be recognized as positive responses.ExampleinputCopy5101120191000000019000011000outputCopyNoYesNoYesNoNoteIn the fourth testcase of the example, initially a=[1,0,0,0,0,0,0,0,1]๐=[1,0,0,0,0,0,0,0,1]. A valid sequence of operations is:Select l=2,r=8๐=2,๐=8 and apply the operation. a๐ becomes [1,0,1][1,0,1].Select l=1,r=3๐=1,๐=3 and apply the operation. a๐ becomes [1][1].
Question
You are given a sequence [a1,โฆ,an][๐1,โฆ,๐๐] where each element ai๐๐ is either 00 or 11. You can apply several (possibly zero) operations to the sequence. In each operation, you select two integers 1โคlโคrโค|a|1โค๐โค๐โค|๐| (where |a||๐| is the current length of a๐) and replace [al,โฆ,ar][๐๐,โฆ,๐๐] with a single element x๐ฅ, where x๐ฅ is the majority of [al,โฆ,ar][๐๐,โฆ,๐๐].Here, the majority of a sequence consisting of 00 and 11 is defined as follows: suppose there are c0๐0 zeros and c1๐1 ones in the sequence, respectively.If c0โฅc1๐0โฅ๐1, the majority is 00.If c0<c1๐0<๐1, the majority is 11.For example, suppose a=[1,0,0,0,1,1]๐=[1,0,0,0,1,1]. If we select l=1,r=2๐=1,๐=2, the resulting sequence will be [0,0,0,1,1][0,0,0,1,1]. If we select l=4,r=6๐=4,๐=6, the resulting sequence will be [1,0,0,1][1,0,0,1].Determine if you can make a=[1]๐=[1] with a finite number of operations.InputEach test contains multiple test cases. The first line contains the number of test cases t๐ก (1โคtโค4โ 1041โค๐กโค4โ 104). Description of the test cases follows.The first line of each testcase contains one integer n๐ (1โคnโค2โ 1051โค๐โค2โ 105).The second line of each testcase contains a string consisting of 00 and 11, describing the sequence a๐.It's guaranteed that the sum of n๐ over all testcases does not exceed 2โ 1052โ 105.OutputFor each testcase, if it's possible to make a=[1]๐=[1], print YES. Otherwise, print NO. You can output the answer in any case (upper or lower). For example, the strings yEs, yes, Yes, and YES will be recognized as positive responses.ExampleinputCopy5101120191000000019000011000outputCopyNoYesNoYesNoNoteIn the fourth testcase of the example, initially a=[1,0,0,0,0,0,0,0,1]๐=[1,0,0,0,0,0,0,0,1]. A valid sequence of operations is:Select l=2,r=8๐=2,๐=8 and apply the operation. a๐ becomes [1,0,1][1,0,1].Select l=1,r=3๐=1,๐=3 and apply the operation. a๐ becomes [1][1].
Solution
The problem is asking to determine if it's possible to make a sequence of 0s and 1s into a sequence containing only a single 1 through a series of operations. In each operation, you select a subsequence and replace it with the majority element. The majority element is defined as 0 if there are more or
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You are given an array ๐ดA containing ๐N integers.Consider the following process:Let ๐=0S=0 initially.For each ๐i from 11 to ๐N in order, update ๐S to either (๐+๐ด๐)(S+A iโ ) or (๐ร๐ด๐)(SรA iโ ).That is, either add ๐ด๐A iโ to ๐S or multiply ๐S by ๐ด๐A iโ .Before performing the process, you're allowed to freely rearrange the elements of ๐ดA as you like.If you choose the rearrangement of ๐ดA and the sequence of operations optimally, what's the maximum possible value of ๐S that you can obtain?This maximum value can be very large, so print it modulo 109+710 9 +7.Input FormatThe first line of input will contain a single integer ๐T, denoting the number of test cases.Each test case consists of two lines of input.The first line of each test case contains a single integer ๐N โ the number of elements in the array.The second line contains ๐N space-separated integers ๐ด1,๐ด2,โฆ,๐ด๐A 1โ ,A 2โ ,โฆ,A Nโ - the elements of the array.Output FormatFor each test case, output on a new line the maximum possible value of ๐S, modulo 109+710 9 +7.Constraints1โค๐โค1031โคTโค10 3 1โค๐โค2โ 1051โคNโค2โ 10 5 1โค๐ด๐โค1091โคA iโ โค10 9 The sum of ๐N over all test cases won't exceed 2โ 1052โ 10 5 .Sample 1:InputOutput244 2 5 231 2 1804Explanation:Test case 11: Choose the rearrangement ๐ด=[2,2,5,4]A=[2,2,5,4]. Then,Add ๐ด1=2A 1โ =2 to ๐S. Now, ๐=2S=2.Add ๐ด2=2A 2โ =2 to ๐S. Now, ๐=4S=4.Multiply ๐S by ๐ด3=5A 3โ =5. Now, ๐=20S=20.Multiply ๐S by ๐ด4=4A 4โ =4. Now, ๐=80S=80.This is the maximum value that can be obtained.Test case 22: Choose any rearrangement and sum up all the numbers to get 1+1+2=41+1+2=4.This is the maximum value that can be obtained.
Suppose a sequence an, is de๏ฌned as follows:a1 = 9/10, a2 = 10/11, an+2 = an+1an
You are given a positive integer x๐ฅ. Find any array of integers a0,a1,โฆ,anโ1๐0,๐1,โฆ,๐๐โ1 for which the following holds:1โคnโค321โค๐โค32,ai๐๐ is 11, 00, or โ1โ1 for all 0โคiโคnโ10โค๐โค๐โ1,x=โi=0nโ1aiโ 2i๐ฅ=โ๐=0๐โ1๐๐โ 2๐,There does not exist an index 0โคiโคnโ20โค๐โค๐โ2 such that both aiโ 0๐๐โ 0 and ai+1โ 0๐๐+1โ 0.It can be proven that under the constraints of the problem, a valid array always exists.InputEach test contains multiple test cases. The first line of input contains a single integer t๐ก (1โคtโค1041โค๐กโค104)ย โ the number of test cases. The description of the test cases follows.The only line of each test case contains a single positive integer x๐ฅ (1โคx<2301โค๐ฅ<230).OutputFor each test case, output two lines.On the first line, output an integer n๐ (1โคnโค321โค๐โค32)ย โ the length of the array a0,a1,โฆ,anโ1๐0,๐1,โฆ,๐๐โ1.On the second line, output the array a0,a1,โฆ,anโ1๐0,๐1,โฆ,๐๐โ1.If there are multiple valid arrays, you can output any of them.ExampleinputCopy71142415271119outputCopy1150 -1 0 0 160 0 0 -1 0 15-1 0 0 0 16-1 0 -1 0 0 15-1 0 -1 0 15-1 0 1 0 1NoteIn the first test case, one valid array is [1][1], since (1)โ 20=1(1)โ 20=1.In the second test case, one possible valid array is [0,โ1,0,0,1][0,โ1,0,0,1], since (0)โ 20+(โ1)โ 21+(0)โ 22+(0)โ 23+(1)โ 24=โ2+16=14(0)โ 20+(โ1)โ 21+(0)โ 22+(0)โ 23+(1)โ 24=โ2+16=14.
Suppose a sequence an, is defined as follows: a1 = 9/10, a2 = 10/11, an+2 = an+1an.Show that 0 < an < 1 for all (positive integers) n.
You are given two integer arrays: array a๐ of length n๐ and array b๐ of length n+1๐+1.You can perform the following operations any number of times in any order:choose any element of the array a๐ and increase it by 11;choose any element of the array a๐ and decrease it by 11;choose any element of the array a๐, copy it and append the copy to the end of the array a๐.Your task is to calculate the minimum number of aforementioned operations (possibly zero) required to transform the array a๐ into the array b๐. It can be shown that under the constraints of the problem, it is always possible.InputThe first line contains a single integer t๐ก (1โคtโค1041โค๐กโค104)ย โ the number of test cases.Each test case consists of three lines:the first line contains a single integer n๐ (1โคnโค2โ 1051โค๐โค2โ 105);the second line contains n๐ integers a1,a2,โฆ,an๐1,๐2,โฆ,๐๐ (1โคaiโค1091โค๐๐โค109);the third line contains n+1๐+1 integers b1,b2,โฆ,bn+1๐1,๐2,โฆ,๐๐+1 (1โคbiโค1091โค๐๐โค109).Additional constraint on the input: the sum of n๐ over all test cases doesn't exceed 2โ 1052โ 105.OutputFor each test case, print a single integerย โ the minimum number of operations (possibly zero) required to transform the array a๐ into the array b๐.ExampleinputCopy3121 323 33 3 344 2 1 22 1 5 2 3outputCopy318NoteIn the first example, you can transform a๐ into b๐ as follows: [2]โ[2,2]โ[1,2]โ[1,3][2]โ[2,2]โ[1,2]โ[1,3].
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